My PC has developed some kind of disk fault - windows sometimes freezes for minutes at a time (especially at boot up) and when I looked in the system log theres 100's of bad disk errors (The device, \Device\Harddisk0, has a bad block. has a bad block.). I believe this kind of error can either be caused by a bad HDD (although the PC has also frozen when plugging in external drives for instance) or a bad controller chip on the MB? Are bad controller chips common? I'm going to try and replace the HDD but whats the best way to test for a bad MB? Many thanks.