you could try this tip[That shell=Explorer can be replaced temporarily with either Winfile.exe shell or
>Progman.exe. These instructions are for Winfile and will get you in, so that you
>can replace Explorer with a new copy. That may be the problem, but I would think
>you'd get an error message. It won't hurt anything to try.
>
>You need to extract a new copy of Explorer.exe. You'll need your OS CD handy, unless
>you have Cab files on your hard drive, normally in C:\windows\options\cabs.
>
>First, you'll need to edit 'system.ini' in DOS to temporarily replace the Explorer
>shell with Winfile. Then you can access your start menu. Boot to the command prompt.
>At the C:\> prompt (press enter after each line) type:
>
>cd windows
>edit system.ini
>
>Now change the shell=explorer.exe to shell=winfile.exe
>
>(Alternatively, you can place a semi-colon like this: ;shell=explorer.exe Then hit
>enter and add the shell=winfile.exe line. Then you'd go back and undo, once you're
>finished.)
>
>>> press Alt+F together to access the File, Save and Exit menu and save the file
>and exit.
>
>> Do a ctrl-alt-del to reboot.
>
>> Once in Winfile, click File - Run, type: SFC then click OK. Choose to extract
>one file from disk. File to extract: Explorer.exe (either point to the location
of
>your CAB install files or your Windows CD, whichever the case). Location to extract
>to: C:\windows
>
>Hopefully, you'll get a message saying the file has been successfully extracted.
>Before exiting and shutting down, click File > Run again and enter system.ini so
>that it opens in Notepad. Edit the line back to shell=explorer.exe Then reboot,
and
>a new copy of Explorer.exe will be in place.