You can also use Smart Utility (http://www.volitans-software.com/smart_utility.php) which will give you a bit more information.
And just to echo Woody - once a drive starts acting flaky, I always replace it. Not worth losing all the data.
For future reference, if you move into an SSD though, beware - those tend to fail completely and catastrophically (all at once) without prior warning. I lost 3 SSD's within two months last fall - different machines, brands and models, but all with the same failure mode. Poof!