i am trying to defragment my dads pc which runs on windows ME. every time i do it it gets to about 5% the says the computers hardrive has changed and it restarts at 0%.
no other programs are running. any suggestionsappreciated

I agree with the previous posters. When Windows 98 did that it was always the screensaver that caused it.

Turn off things like screensavers, & any power management options that might be set to on the computer. Also close as many programs as you can (right click on the icons in the bottom right of your screen & select exit or shut down etc). Especially remember to turn off any antivirus programs as some to a constant scan of your system to prevent infection. Once thats done run the defrag program again & it should work fine.