Troubleshooting communications problems can be a frustrating pastime. There are so many parts to any computer connection it’s often hard to isolate where the problem is located, let alone pin down exactly what’s wrong. The trouble could be with your hardware: modem, router, Ethernet or wireless card, the cables, or interference from other devices. It could be with your software: your communications settings or the security software on your computer or built into your router. Or the problem could be out of your hands: an outage with your Internet Service Provider (ISP), or a glitch on the remote computer or web site.
Patience and a systematic approach will help you figure out most problems, and despite how messy things can get, it’s surprising how often the solution is to flick a switch or two.

Tip: Use the friends network

Before you spend hours troubleshooting, try phoning a friend who uses the same ISP to see whether they can get online. If they’re experiencing problems, too, it’s likely your ISP is at fault. Get on the phone to technical support. Sometimes, though, an ISP will have a problem which affects only a section of its subscribers. This may be the case with email problems, when accounts are split between different mail servers and your server happens to be the one that goes down. If your friend can get online, have them check the ISP’s service status page to see whether any outages have been reported.

Trouble accessing a web site

Some hard-to-diagnose web access problems can be solved simply by clearing your cache and cookies. (Click for full-size screenshot.)

A web page that won’t load in your browser provides a good example of how a seemingly simple problem may have a myriad causes. As the following troubleshooting steps indicate, the cause may be trivial or it could prove to be decidedly vexatious:

  1. Did you type the address correctly? Take a look at what you typed in the address bar and make sure it’s correct.
  2. Do you have the right address? Is it, or Use a search engine to check the spelling and make sure you have the top-level domain – the last part of the address – correct.
  3. Does the web page exist? A 404 error displayed on a page usually indicates the page doesn’t exist. You might have the correct name for the site, but an incorrect or out of date page link. Try accessing the main page of the site – instead of, for example – and search for the content from there.
  4. Is the site busy? Wait 20 seconds then try to access the site once more. Often a site may be temporarily busy or its server or connection may go down for just a few seconds. Wait a short while then try again.
  5. Can you access other web sites? Try usually reliable sites such as or If you can connect to other sites, it’s almost certain the problem lies with the site you’re trying to access. It could be down for maintenance or experiencing some other problem. Try again later.
Ignore script errors

Set Internet Explorer to ignore script errors – there’s nothing you can do about them, they’re simply mistakes in how the site has been written.

To double-check the problem is with the web site, clear your browser’s cache and cookies, restart the browser, then try to access the site. Or, if you’re using Firefox, try accessing the site with IE. Some sites work only in Internet Explorer (it’s rarely the other way around), and sometimes, even if you can’t access the site with a different browser, the different wording of an error message will help you figure out what’s wrong.

If you can’t access other sites, then it’s time to start troubleshooting your Internet connection.

Trouble accessing the Internet

Here’s where things get really interesting. If you can’t access the Internet at all, start by checking your hardware:

  1. Is your modem on? Check that all the usual lights are lit or blinking as appropriate. It helps, of course, if you know which lights are usually lit solid and which flash, so if possible position your modem (and your router) so you can see the status lights.

If the lights are not lit correctly – or if you’re not sure whether they are – reboot your modem: disconnect the power cord, wait about a minute, then reconnect the power cord and wait for the lights to come on. Then try your Internet connection again. If the lights are not lit, ensure the power cord is properly seated, then check the Ethernet or USB cable between your modem and your computer. Don’t just give the cables a look over; instead, disconnect each end of the cable and plug it back in securely. If you’re using an Ethernet cable, it should make a click when it seats properly. If you’re using a USB cable and have it connected through a hub, take the hub out of the loop: disconnect the USB cable from between the modem and the hub and connect it directly from the modem to a USB port on your computer. Also, if you’re using a USB port on the front of your computer, try disconnecting that cable and plugging it into a USB port on the back of your computer; sometimes, the ports at the front do not have sufficient power to do the job.

Tip: Prepare for trouble

Most ISP’s list their technical support phone number on their web site (although you may have to dig around to find it). Write it down now, before you have a problem with your Internet connection, and stick it somewhere handy. Also, make sure you have a copy of your router’s documentation on hand – you should find a downloadable version at the manufacturer’s site.

If the modem lights still fail to come on, give your ISP a call. There’s a good chance there’s something wrong their end.

  1. Is your router on? If you use a router in conjunction with your modem, make sure the appropriate lights are lit and check its cables, too. Even if the correct lights are on, try resetting the router by disconnecting its power, waiting a minute, then reconnecting the power.

If the router’s lights fail to come on but your modem appears to be working, your router may have failed. Routers have a tendency to go bad silently and without notice. One way to check whether the router is kaput is to disconnect your computer from the router and reconnect directly through the modem. If you can successfully connect to the Internet without the router intervening, there’s a chance the router no longer works. It’s also possible that the router’s internal firewall or security settings are causing a problem, but in that case, its lights should still display as usual.

Sometimes, rebooting the modem and the router separately is not enough, but a full reboot may do the trick:

  1. Switch off your computer and unplug the modem and the router.
  2. Wait a minute.
  3. Plug in the modem and wait for its lights to come on.
  4. Plug in the router and wait for its lights to come on.
  5. Switch on your computer.

Check for viruses and malwareTesting software settings

If the old unplug-and-reboot routine doesn’t help you, check your software settings.

Before you do anything else, run your spyware and anti-virus scanners to make sure your computer is clean and to ensure that a browser hijacker hasn’t taken over your browser. If you find a problem, clean it out, reboot your system, then run another scan to make sure all vestiges of the infection have been eliminated.

Malware can also rewrite your hosts file. This file is used to associate a particular Internet hostname with an Internet Protocol address (the 32-bit numbered addressing system used on the Internet). There are legitimate uses for the hosts file, such as redirecting known malicious sites to a safe site. The trouble is, malware can use the same file to redirect you from safe sites to unsafe ones. Good security software should warn you if your hosts file has been tampered with. In some cases, an entry in the hosts file may interfere with your ability to reach a site. To test this, rename the hosts file:

  1. Locate the file. In Windows 95, 98 and Me it’s in the Windows folder, which can be accessed by clicking Start -> Run, typing %windir% and clicking Open. In XP, Win 2000 and Vista, it’s in the system32\drivers\etc folder, which you can open by clicking Start -> Run, typing %systemroot%\system32\drivers\etc\ and clicking OK.
  2. Rename the hosts file (it has no extension) to hostsold.
  3. Reboot your computer.
  4. Try to access the Web site once more.

Note that if you or a system administrator have set up legitimate entries in the hosts file, renaming the file will disable these entries. In that case, if you determine that an entry in the hosts file is causing your problem, you’ll need to edit the hosts file, delete the problem entry (or entries), rename it hosts and reboot.

Check offline mode

Make sure you’re not working in offline mode. Click to remove the tick beside Work Offline in your browser’s File Menu.

Once you’re sure your system is clean, temporarily disable your firewall and then test your Internet connection again. Make sure you access a site you know to be safe while your firewall is disabled. If disabling your firewall solves the problem, you’ll need to configure the firewall to permit your browser to access the Internet, make sure your security software is not blocking the specific computer you’re using, and then re-enable the firewall. The process differs from product to product, so refer to the documentation for your security software.

If the problem persists and you use a router, disable its internal firewall as well. You should be able to do so from the router’s browser-based configuration screens. Refer to the router’s documentation to find out how to do this with your particular model.

Still having trouble? If you use Windows Vista, it has fairly sophisticated network diagnostics. Right-click the Network icon in the notifications area and select ‘Diagnose and Repair’. Vista also provides access to network diagnostics directly from Internet Explorer. If you try to connect to a page and fail, you should see a Diagnose Common Problems link on the page. Click the link to activate the diagnostics.

Troubleshooting wireless connections

Wirelessly connected computers have their own troubleshooting needs. In addition to ensuring that the router and modem are functioning correctly, try these steps if you have trouble connecting:

  • Check that the wireless switch is on. Many notebooks have a switch on the side or front of the computer which activates and deactivates the wireless network card. Make sure it’s in the on position.
  • Ensure the signal is strong enough. Your wireless connection software should provide an indication of the strength of the signal available. If it’s low, try moving around to see if you can find a better location. Distance and intervening walls will both diminish the signal strength. If you can’t get closer to the router or access point, consider buying a range booster (make sure it’s compatible with your router) or, if it can accommodate one, add an external antenna to your wireless network adaptor.
  • Check for interference from other devices, such as cordless phones. Switch such devices off temporarily or move farther away from them. Alternatively, try setting your router and wireless network adapter to use another channel.
  • Make sure you’re using only one wireless configuration utility. Windows provides a wireless connection utility, and most notebooks with built-in wireless also provide their own wireless connection software. If you install a wireless card it, too, will probably include a connection utility. Make sure only one of these utilities is active, otherwise you may end up with a conflict which prevents you from connecting at all. If necessary, uninstall one of the utilities.

Tip: Suspect leads

Sometimes it’s the unlikely thing that goes wrong. A cable, even a new one, might be a dud. Swap out the telephone, Ethernet and USB cables, one by one, to see whether they’re causing your problems. This is always worth trying before you ditch a seemingly defunct router or modem.

Locate a hidden wireless network

Locating a hidden wireless network

If you can’t get any wireless signal at all, it may be because your router is configured to hide its network name, also known as the SSID (Service Set Identifier). If that’s the case, you won’t be able to ‘see’ the router unless you’ve previously connected to it. In order to connect, you’ll need to enter the settings manually.

In Vista or Windows 7:

1. Right-click the Internet Access icon in the taskbar tray and choose Open Network and Sharing Center from the context menu.

2. Click ‘Set up a connection or network’.

3. Click ‘Manually connect to a wireless network’ and then type in the network information, including the network name.

In Windows XP:

  1. Click Start -> Network Connections (or Start -> Run, type ncpa.cpl and click OK).
  2. Right-click Wireless Network Connection and select Properties from the pop-up menu.
  3. Click the Wireless Networks tab in the Properties dialog box and click the Add button.
  4. Type in the settings for your network.

Tip: Be lazy with addresses

Don’t feel you have to type complete web addresses. Browsers are very forgiving about how you format the address. It used to be you had to get the address exactly right, for example: Then browsers started letting you leave off the http://, thus: With most recent browsers, you can get away with leaving off the ‘www.’ and sometimes you can even get away with leaving off the top-level domain name (.com, .org and so on). If you do type in the full address, the browser will correct your typing if you use http:\ instead of http://.