No internet connection, network connections empty

My brother has lost all internet access on his laptop. (Windows XP Pro SP3)

He started having issues with his wireless a while ago, when no one else in the house was having trouble. I then tried connecting him with the ethernet cord, and at first that didn't work. I used the internet repair that comes with SuperAntispyware and it then worked. I tried using the Linksys EasyLink Advisor (came with wireless router), and it reported that it could not find a functioning network adapter. During this time I noticed that his Network Connections has no icons, and using the "create new connection" wizard does nothing. SuperAntispyware repaired the internet and wireless, but still no icons under Network Connections. Yesterday, however, he lost his connection again and SuperAntispyware doesn't help it now. We have run AVG 8.5 Free, SuperAntispyware, MalwareBytes, Ad-Aware AE, and Spybot Search and Destroy, and all of them come up empty, he uses Commodo Firewall, all these programs and Windows XP are currently up to date, and no other odd behavior has been noticed, so malware seems unlikely.

In Device Manager, the network adapter appears and reports that it is working. One of the Windows help suggestions is to uninstall the adapter and allow Windows to detect and reinstall it. I'm afraid to try that because once the drivers are uninstalled, I don't know how to get them back. (I learn fast, but I haven't done this before). If Windows doesn't detect and install them, what would I do then?

I have tried a system restore to last month, when his internet was still working fine, but nothing has changed.

There is a possibility of a conflict with ThinkVantage Access Connections (He has an IBM/Lenovo Thinkpad). I have always used the Windows Network Connections, so I am unsure what he might have done there, or what I might have done trying to use the Windows interface instead of the ThinkVantage one. :banghead I'm concerned that I've started doing more harm than good.

My brother wants his internet immediately of course. He's willing to reformat, but he has an OEM installation and no installation or recovery disk, so I don't know how to continue.

I'm willing to try anything, but looking around the internet has turned up a mountain of possibilities, and I'm worried I'll make things more difficult by doing the wrong ones. I'll provide any information you need to narrow down the options.

 

At my brother's urging, I just went ahead and did it. I opened Device Manger, uninstalled all three network adapter/cards/whatever, then restarted the computer. All three seem to have reinstalled and appear to be working fine now. Network Connections has icons again. Since I don't know what caused it, it may happen again but we'll face that when it happens. Probably the conflicting programs.

Source for this fix and several other detailed steps to try: http://support.microsoft.com/kb/825826

I found that Microsoft article surprisingly readable.