Hit Ctrl-Alt-Del and load Task manager.
From Task Manager, execute EXPLORER.EXE from; File --> New Task (run)
The desktop should load. Reboot the PC and see if you can logon and get the desktop again
without loading TaskManger and runing Explorer.exe .
If this did not help try the following:
If explorer.exe is not in C:\WINDOWS\ then insert
your Windows CD and, using the 'Task Manager', run
the 'System File Checker' utility with this command:
sfc /scannow
If the 'System File Checker' didn't replace it, boot
to the Recovery Console with the Windows CD and copy
explorer.exe manually:
1. Insert the Windows CD and restart.
2. When setup begins, choose the "Repair or Recover"
option by pressing "R".
3. Once at the command prompt, enter:
copy D:\I386\EXPLORER.EX_ C:\WINDOWS\
(Change drive letters accordingly)
4. The file, "EXPLORER.EX_" is compressed and should be
automatically expanded on copy. If it doesn't just enter
this command:
expand C:\WINDOWS\EXPLORER.EX_ C:\WINDOWS\explorer.exe
5. To exit the Recovery Console, type: exit.