I have just had a new CD drive installed oon my PC that is running XP. When I got it home and switched it on i got 'checksum does not match the computer checksum'! The guy in the shop said it was now a failed Hard Drive and I need a new one! Is this a load of rubbish or could he be telling the truth? The computer has always been fine until he installed this new cd drive?? Please help before I get ripped off by this person!!