Thanks for the prompt reply!! When this happens, F8 will not allow start up at all, either in safe mode or any other of the options, all attempts land up with the missing or corrupt file problem. No new software installed prior to problem either! Hard disk was new 4 months ago, as is the rest of the pc. Only option given is to reinsert XP disk, and attempt a repair, but no info on how to effect this. Have another hard drive which runs ME OK! Once again, thanks!! Owain