My icons change on my desktop -- or disappear, leaving regular
folders, etc. In cases where I've created a shortcut to desktop and a
domain's icon is created, it'll be gone within a week.
Is there a repeatable pattern to how long it takes to disappear?
I use Windows Defender, Ad-Aware daily, and run One Care weekly.
You mean Ad-aware, not "Ad-Aware daily", right?
How current? Within the last day or so is "current".
Did you update them just before using them? That's best practice.
You didn't list any anti-virus. Do you have it installed and is it
updated? If you have none, Symantec and McAfee both offer online scans
for free - they take a lot of time to run but work well. If you don't
have AV, get it. AVG and AVAST are free ones available.
In the future you also need to install a firewall such as at least XP's
(available as of SP2) or better yet something like ZoneAlarm.
WinPatrol is a handy program too. EVERY program that runs needs to
be given permission at least once. Lots of other features too. Free.
Add Spybot Search & Destroy to your list of malware tools.
Look in Event Viewer logs for hints.
It could also be simple file corruption:
It might be faster and less frustrating to simply back up your important
data and reinstall XP from scratch, but try a Repair Install first.
HTH some