I too have this problem

lap top 6 months old - start having slow start up - decide to do the usual defrag - complete scan of hard drive - fix errors etc
after long scan reboot warns me of hard drive failure

reformat 3 times - same thing - computer acts fine

surely scan has just found and attempted to fix a bad block/ ? now thiks hard drive is broken - isnt this just a OS trying to be too clever and actually anouncing a minor issue as a complete hard drive failure ??