Don't you hate it when your wireless does this to you? I hate to admit it but I encounter this problem far too often. I would hold off investing in a removable wireless device such as the USB adapter until you've absolutely determined that your wireless card is the problem. There are a number of things you can do the check out you notebook before spending money. Since you powered down your router and your 2nd computer isn't having issues this probably rules out the router and modem as the bad guys--for the moment. Try one, or all, of the following three tests before going forward.
TEST #1:
Make sure you didn't disable your wireless capability by moving the switch on your notebook which enables Wi-Fi. Manufacturers sometimes use sliding switches and put them in places that make it easy to inadvertently turn off the notebook's wireless capability. If it was off your Internet connection should be re-established once it's turned back on. If this wasn't your problem try Test#2.
TEST #2:
One of the most frequent villains is the inability of your notebook to to get a valid IP address which is assigned by your router. This is one of the first things I check when my connection drops for no apparent reason and I cannot get it back easily. To trouble shoot this try the following:
Check the status of your network connection. This is done by checking the icon (two overlapping computer monitors on the task bar). If you have a red X over the computers you do not have a network connection (to your router). If you don't have the X and move your mouse over the icon and it will say: "Access: Local Only" or "Access: Local and Internet". The latter is what you want but apparently don't have.
If you don't have a network connection or you have "Local Only" connectivity the next step is to check your computers IP address. This address is normally automatically assigned by your router to your notebook when you turn it on. Run the Vista accessory program called "Command Prompt". When the window pops up type "ipconfig.exe" next to the C:\...> prompt and this will tell you your computers IP address(es). Check under "Wireless LAN adapter Wireless Network Connection" and note the IPv4 Address. If the address begins with 192.168.xxx.xxx the router is properly giving your computer a usable address. If you see an address that begins with 169.254.xxx.xxx, or you don't have any address, the router and the computer are not correctly connecting to one another and Vista is giving you a default IP address which is useless for getting to the Internet.
If you have an IP address problem, it doesn't necessarily mean that any of your hardware is defective. It only means that they have lost their way--as crazy as this might sound--and your goal is to re-sync everything. First, try and re-establish a manual connection from your notebook to the router by left clicking on the task bars network icon and choosing "Connect to a network". You should get a list of available wireless networks which includes your router. Right click on your router and choose "connect". If you're back online you're done. If you're not allowed a connection due to an invalid security key you may have to reenter the security key into your notebook, then try again. For some reason wireless clients occasionally just "lose" their security key. This is done by right clicking on the router and choosing "properties". If one of these two steps don't fix the problem try the next test.
TEST #3:
For the record I have no clue why the next procedure works but this solution has bailed me out of this problem many, many times. Disable the notebooks wireless capability by turning off the wireless switch on the computer. Then use an Ethernet LAN cable to plug your notebook directly into your router. If you do this correctly, you should now have "Access: Local and Internet". Now launch your browser, surf the web and make sure everything is working OK. You might also check your IP address to make sure the router and computer are on good "speaking" terms again. You should have an IP address in the 192.168.xxx.xxx range. If everything is functioning normally shut Windows down and unplug the network cable. Turn the wireless switch back on and reboot your notebook. If you have normal wireless Internet everything is back to normal and you're DONE. At this point if you don't get an automatic router connection you may have to manually reconnect using the procedure in Test#2 above.
If neither of the above three procedures work. There are still a couple of things that should be done before declaring your notebooks Wi-Fi to be DOA. But first try the above. Good Luck.
