Hey there, gperez.
If you're having issues with your drive and you still have access to it, I'd recommend that you backup any important data, which you might have on it and you can't afford to lose, just to be on the safe side.
As for your question, here's an article with a bunch of HDD diagnostic tools (both brand related and 3rd party ones) so you can have your pick: http://pcsupport.about.com/od/toolsofthetrade/tp/tophddiag.htm. I'd recommend that you go for the one provided by the HDD manufacturer.
Hope that helps. Please let me know if you have any questions.
Boogieman_WD