XP missing desktop icons and taskbar

Just started happening today, XP SP2 boots up but only shows the desktop wallpaper, no icons, no taskbar. CAD brings up task manager but it starts running slow and blocky whe you try and do anything. Safe mode brings all up as usual.

Spent a couple of hours Googling and trying various things before posting here, some are listed below, none of them have worked:

Restored explorer in the registry using: "Shell"="explorer.exe" from shellfix.reg tool.

Restored explorer.exe file from another comp.

Tried LKGC and System Restore.

Checked 'run' in registry and msconfig startup values for nasties.

Scanned for F-Nimda using fix tool from F-Secure.

Ran ComboFix which crashed so currently running it in safe mode.

Next course of action is to pull the hard disk out and scan it in another machine as I think this is viral. System is using Avast fully updated, A-squared and Spybot all updated with Kerio Personal Firewall.

Hoping someone here has come across this before and has another quick fix before I pull the thing apart!

Does task manager show anything using a lot of the cpu?

Nope, 'system idle process' is at 99.

Also run full scans with Avast, A-Squared and the Fix Vundo tool.

Ran a Hijackthis scan and found nothing suspicious in there.

Still no desktop. Help!

Ok, got the desktop back - seemed to be a corrupt Windows account for the Administrator.

Fixed simply by logging on as another user, then back out again ... doh - could have saved me 6 hours!

Anyway will monitor and post if it happens again.

Would you recommend installing SP3 to fix any flakey files that may still be hanging around?

No comments on SP3 then?

Sp3 Yes, do it. There was a problem with some AMD puters before:

A former Microsoft security expert has coded a fix for the endless reboot problem that has been causing some users' PCs to crash or enter an endless reboot loop after installing Windows XP service pack 3. Microsoft earlier this week said the problem, which stems from a glitch with an Intel power management driver and primarily affects Hewlett Packard desktop PCs with AMD processors, is the result of OEMs using the same image for both Intel and AMD based PCs. (source: crn.com)