Help! Serious Windows problem...

I was wondering if anyone could give me a hand with a problem I'm having. I'm working on a friend's computer, and I really can't figure it out. Basically, sometime yesterday explorer.exe just stopped working. Earlier one of her friends installed Norton on it (which I'm sure isn't helping) but for some time it was still alright. As it stands, I can't access or use anything involving the explorer processes. This means no GUI, no downloading, no file manager, often no "yes or no" prompts...I'm running everything from the command prompt and iexplore.

Whenever I try to run explorer.exe it'll sit for a while, then give the familiar message about sending an error message to microsoft. I'm running a virus scan right now (online), but I'm wondering if anyone else has some ideas? chkdsk is finding some stuff, but running chkdsk /f and rebooting comes up clean. Norton is as disabled right now as I can get it.

try using a linux live CD or Windows PE and replacing/restoring a copy of explorer.exe

does it do this for all profiles? safe mode?

Yah, the first thing would be to get a knoppix CD and see what magic you can work with that.

Now, I am a bit skeptical that norton would cause a problem with explorer. After all, that is supposed to be the "real authentic official" way that all computers must be or you just don't have a real computer. Seriously, most corporations pee away millions every year to run norton on top of explorer and no real problems are evident.

However, if you are able to get a command line, have you tried running scanreg? I think that if you run scanreg/help you will get a list of the possible command switches. There is one in there that will return your registry to the last state that you were able to get a sucessful boot from. However, unless you fix broken computers every day, I would only expect the guys who hang out in the MS/OS forum to just know that stuff.

in the cmd window, you could try a sfc /scannow as well.

I'll try those commands, thanks. I haven't done much with knoppix, but playing around with the restore cd is the next option. Just to confirm, I ran two different virus scanners and both came up clean.

*Edit* Scanreg doesn't do anything...says it's not valid. Hmm. The SFC is one I've used before though, and we'll see how that goes.

Replaced explorer, which I was able to do from within windows via the command prompt. It didn't have any problem overwriting it, as it wasn't running anyway.

Yes, this occurs for both the Administrator profile and her profile, and happens in safe mode too. Restore Last Good Config doesn't work, either. Replacing explorer seemed to help...I get a GUI for about 10-15 seconds before it'll crash and restart again. That was some of it, it seems, but definitely not all.