you might be able to take a copy of a working notepad.exe and put it back into his windos\system32 folder and see if that helps.
You could also try to use system restore to a point before it went bad (unless it's disabled).
I won't be at my friends pc til the weekend, So i am learning Dutch, just incase first, If it don't work out we can always rename his pc "The Flying Dutchman" HEH! They ought to make a movie or a book with that Title! I will be in dutch, i mean touch and let you know how it works out!LOL Thanks Guys, Tom