My computer has been auto-restarting on its own and i was told that if i had the OS CD I can fix my computer by doing a repair. The only CD I found was the restore disc. We called Best Buy and they said that is the OS CD because my computer is from 04. We d/l and then after waiting a long time a message popped up and said: Windows can not start the following was missing or corrupt: <Windows root>/system32/ntoskrnl.exe. What would I have to do to fix this issue?