Sounds like you have the VX2.BetterInternet Bundle installed. I just wrote an FAQ on it's removal but I'm not sure if it's available to view yet. Here's the short version on how to remove it:
Open regedit and navigate to HKLM\Software\Windows NT\CurrentVersion\Winlogon\Notify. See if there is a key beneath Notify called Guardian or GuardianRHRFQ; something like that. If there is, click on the Guardian key and look at the DllName value for the name of the file causing the trouble. You will have to boot to a DOS boot floppy or, if you have an NTFS file system, to the OS CD and go into Recovery Console. Navigate to Winnt\System32 and delete the file. If it won't let you delete, use the attrib command to remove the read-only, hidden, and system attributes and then delete.
Reboot and run Ad-Aware to clean up anything left over.