I have not come across this before, but it sounds as if there could be a Hardware problem. It would be as well to eliminate this as a possibility before going any further. Use a bootable floppy disc to load up a basic DOS system. Now try to scan the C:\ drive for files by typing
The screen should rapidly list all the files and folders in the route directory followed by some sizing data. If you get an error message, report it back.
Now attempt to copy any one of those files by using the instruction
copy c:\<filename>.<fileextension> <filename>.<tmp>
Once again thge screen should show the instruction as being completed. If you get an error message, report it back.
If both of these work, the likelihood is that the problem lies elsewhere - if you get an error message, you may have a problem with the Hard Disk requiring replacement.
Also a couple of questions.
1 The last time the system loaded correctly, did your friend do anything with the system itself, even to the extent of deleting any files directly (not via a proprietory package) or notice anything go wrong before switching the PC off normally.
2 Did the PC close down normally last time.
3 Has the PC been making any strange noises lately.