In most cases not being able to connect to a wireless network is an easy fix. If you have a laptop there may be a on/off switch for your wireless card some where. In a lot of cases, they have a switch so that the wireless card is not taking up power. Make sure that your wireless card is on. Check the edges of the laptop and above the keyboard. There will be a logo for the switch. It will, in most cases, look like a wireless antenna or radio waves. In some cases, you will have to hold down the FN key and press a button in the function part of your keyboard. F1 through F12.

From there, make sure that you are connected to the correct wireless network. There are a bunch of wireless connection managers out there. However, if you are using the built in windows wireless configuration manager, In Windows XP right click on the little wireless icon in the lower right hand corner next to your time. Left click on view available wireless networks. Click on your wireless network and click connect. In Windows Vista/7 right click on the icon and select connect to network. Make sure that you are connecting to the correct network. You may also be using a Intel wireless connection manager, or something from the manufacturer. Most programs are self explanatory and can be found under start, programs, ext...

If your still having trouble, try power cycling your modem and router. Wait several minutes and try again. It won't hurt to try rebooting your computer either. If possible try more then one computer to narrow it down to the computer or wireless router. If another computer is connecting, it would be good to narrow things down further. Try the computer at a public hot spot if at all possible. Such as Starbucks or your local library. If the computer is working at a public hot spot, the trouble is being caused by wireless interference. It seems odd, sure, that one computer is working fine and the other is not in some cases. However, trust me different wireless cards can be better in different frequency ranges. It doesn't really mean it's a better card either. It is likely that there may be a wireless channel that will work good for both cards. Check my document on how to change the wireless channel at http://www.reliabletechnicians.net/interference .

If your computer will not work on a wireless connection at a public hot spot either. It could be a defective card or a problem with the drivers. Before continuing, it is good to make sure that you have the drivers for your wireless card. You may have a cd that came with it and/or can get the drivers from the manufacturers web site.

Depending on the card and, if at all possible, it is best to remove the drivers from add/remove programs(Windows XP) or programs and features(Windows Vista). Both are located under start, control panel. Reboot the computer and reinstall the drivers from the cd or download them from the manufacturer's web site.

There are a lot of cases where the drivers will simply be built into windows. In that case, simply go to start, control panel, hardware and/or device manager. Warning, if the drivers are not built in, you follow my directions, and can not get the drivers for your card. I do not assume responsibility. Click the plus sign next to network adapters, right click on the card, left click on uninstall. Now click action, scan for hardware changes. If all went well, all it did is put it right back there and no further action is required. Try rebooting your computer and see if you can connect to your wireless network again. If you continue to have trouble, there is a good chance that it may be a defective wireless card. Visit the manufacturers web site and contact them about warranty information.