i use hard disk sentinel. it can run some tests and tell you how long your drive (not sure how accurate as i don't have any that will die soon) will survive if there are problems.
You can test your drive for errors using your O/S tools. Open Computer - and right click over your HDD to open the properties window. You click on the tools tab and can check drive for errors.
Um... you see this is the problem. Every test result is ok, yet some files (only audio files so far, quite strange isn't it?) are corrupted. I do not know whether it's the hard drive or those files were damaged in the first place.
