Note, this is not for the faint of heart (and having some DOS knowledge helps).
I would suggest booting up in DOS mode and running the 220clean program. This utility checks the OS files and cleans up extraneous information. It can also wipe show files which may be good if you have any that are corrupt. To boot into DOS you have to have a regular keyboard connected, and you hit control-break when you see the
strand splash screen. You should get a DOS prompt, and you should be able to just type "220clean" followed by enter to run the utility. I cant remember the shutdown command (though it may be "shutdown"), but then try rebooting and see if that helps. I'll keep thinking about other things to try and get back to you.