Everyone seems to have good advice, I would try reseating all the cards & the memory chips (alhough I would expect an error beep for faulty chips) & checking the cables first, but I doubt it is this my guess is that either your hard disk is FUBAR'd or Windows is (although I find the re-booting puzzling )have you got SMART switched on? or is it not supported. Personally I would stick another hard drive in load up windows & set the old drive up as a slave get the info off of it then re-format it & start again. Keep us posted