Hello
as beLIEve said, use a third party tool, like:
hdtune is very good!: http://www.hdtune.com/
if you are in linux: smartctl -a /dev/sda
look for:
Reallocated sector count
Current pending sector
Offline uncorrectable
Multizone error rate
there are a lot more that are important, but these 4 are the worst ones
or post here the screenshoot.