Problem with my External HD

[peachy]

Ok...

before i left my desktop computer went, so i ordered a new one before i got back. When i got it here i started transfering stuff from my external HD to the new tower and after awhile I got this message and it wouldnt register my ex HD anymore

"F: is not accessible - the request couldnt be performed because of an I/O device error"

can anyone tell me what this means?? I am kinda stuck until I figure it out? Is it the actual ex HD or maybe the cable link?? I tried to hook it up to my laptop and get the same error, sometimes it doesnt even register its hooked up until i unplug it then it pops up for a second and goes away.

someone please help....