External USB hard drive problem

Lately, when I hook up my USB hard drives, they're detected right away and show up in My Computer right away, but after that, they respond really slowly. On the first one, if I explore for it for a bit it will stop responding, and I'll either get an error ("My Computer" has stopped responding, click to end now, etc) or it'll just stop responding and I'll use the task mgr to close it. On the 2nd one, if I start to explore it, I get a DEP Prevention error on Windows Explorer and I have close and restart Explorer. This just started maybe 3 days ago. The first one works fine on a friend's Win2000 PC (I have XP Pro SP2), I haven't tried the 2nd one. I can burn files from either HD w/o problems. Any ideas?

BTW- I ALWAYS use the 'Remove Hardware Safely' option....

 

>>> bump <<<