go to Start > run and type "cmd" without the qoutes
type CHKDSK/R in the console and schedule a scan for next restart, if you have other partitions say a D: drive for example (not devices such as CD/DVD) type the partition letter in the console, and type CHKDSK/R again.
Windows will scan for bad sectors and try and remove them (it marks the blocks as bad and prevents using them), it will report at the end how many kb of bad sectors you have (hopefully none)
if you miss the end report, you can use windows event viewer to look at it.
be warned, if you have a large hard disk, this may take anything between half an hour, upto a hour and half!