Uninstall, then reinstall the software for the wireless adapter.

Then run the WinsockXPFix tool from the link below to repair any connection software that may be damaged:

http://www.majorgeeks.com/WinSock_XP_Fix_d4372.html

And have you checked for malware? Try downloading, installing, updating, then running the free SuperAntispyware program from the links below.. On a separate, clean computer, download the installer file and manual updater from the links below.. Copy them to a CD or flash drive, then transfer them to the problem machine. Run the installer file to install the program, then bring it current by running the manual updater.. Once that's done, run a full system scan.

SuperAntispyware
http://www.superantispyware.com/

SuperAntispyware Manual Updater
http://www.superantispyware.com/definitions.html

Hope this helps.

Grif