How do i check my hard disk for errors?

Sat Feb 19 07:01:56 UTC 2005

I had to reinstall fedora bcoz i couldnt remove packages and
essentially had to reformat /usr and /.
And now i fear my HDD has produced errors.When Fedora boots it gives
msgs like "/usr clean few numbers/few number blocks"
When i right click to /usr folder i get this reading as well- 
103560 items, totalling 1.8 GB
(some contents unreadable)

Is my HDD damaged.How do i cheack and correct it?Plz help :((
rajev
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© 2005 Rajev Mhasawade