Despite repeated attempts, I'm unable to install XP Service Pack 2. It proceeds through most of the installation process, then aborts with a message box stating that installation has been terminated because the "handle is invalid".

I'm running an HP Pavilion with a 1.6 GB AMD chip, 512 MB RAM, plenty of hard disk space. I've not detected any other problems. Went through HP's suggested list that included emptying Recycle Bin, running Scan Disk, Defragging the hard drives, with no success. I also ran SpySubtract, AdAware, and Spybot. I don't suspect a virus: I'm behind a router, run Zone Alarm and AVG.

Any thoughts?

L