Explorer.exe won't run

[onedrum]

I've been working with this computer for about a week now, and the
essential problem to solve seems to be that explorer.exe starts and
then stops after just a fraction of a second. I have no icons, no
taskbar, no start menu in normal mode, safe mode or diagnostic mode,
but I can hit Ctrl+Alt+Del to bring up the Task Manager. I can run
just about every program on the PC by going to File->New Task in the
task manager, but explorer.exe, iexplore.exe and the Control
Panel(control) just start then immediately disappear. The individual
components of the Control Panel work fine though(appwiz.cpl,
desk.cpl...). I've scanned the PC with AVG, Spybot, Adaware, CCleaner,
Ewido, Hijack This, and a few other things, and though it was virus-
and spyware-infected in the beginning, it doesn't seem to be now.
Ultimately, considering that the problem persists in diagnostic mode, I
think it's a problem in Windows somewhere, not spyware or viruses. The
same problem occurs if I create a new user as well. I've also tried
expanding explorer.exe, running sfc /scannow, and doing a repair
install. System restore is enabled, but much to my dismay there is not
a restore point from before the problem occurred, because reimporting
an old registry would have most likely fixed the problem I think.
Certainly, a reinstall of Windows would fix the problem, but (1) it's a
client's computer and they cannot replace all of the programs and (2) I
would just like to figure this thing out! We've had the "no icons, no
taskbar" problem many times, but this one is more in depth that
anything I've ever seen! Thank you guys for your time and I would
definitely appreciate any ideas!
--Bob

 

[neil]

If you run explore.exe from taskmanager does it run ok or stop immediately.
If the latter perhaps a repair install will fix it.
Neil

 

[onedrum]

When I run explorer.exe from the task manager, it stops immediately,
but I've tried a repair and it didn't fix it. I also tried renaming
explorer.exe and expanding it from the XP CD. The original and the
expanded versions were the same size.

 

[neil]

You don't say if you are using XP Pro or Home but the test should be the
same. Can you login as "administrator" (if Home Edition then you need to be
in safemode) if you can and it runs OK then you have a corrupt account. The
only way I know of sorting that out is to backup the important stuff and
create a new account name (or if you feel brave, delete the old one then
create again).

If the built in "administrator" account wont work then I think you will need
to re-format.

best of luck
neil