Characters/words in display and wireless profiles disappearing (Trojan?)

Greetings,

Dell1505 laptop running XP pro, Intel PROSet/Wireless. Display problems occur like the text of entire lines from my outlook e-mail list disappear. Usually followed by error dialog boxed that pop up without any text. Degrades to the point that when I go to shutdown text is missing from dialog boxes. When I reboot I often find that the profiles for my Intel PROSet/Wireless is gone. Rebooting solves problem for a while but eventually comes back. First started happening with one user account so I thought that it was a corupted account. Now happening with another account.

Some error messages that have popped up why this is happening are like:

1) Driver problem, driver not installed

2) image not found...

3) cannot access location 0x....

etc.

The disappearing of text in the display occurs for OS, Outlook and anything running. SOmetimes text of icons on desktop change appearance.

I am running NIS, Sana Security Primary Response, and adaware. Have also checked for rootkits. Scanned multiple times with various malware/virus programs online and downloaded but nothing came up.

Any ideas?

Thanks for your help in advance!

Cheers,
Marc