Anyone had similar issues like this before?

My external HDDs (let's call them xHDs from now) seem to like me less and less over time, as if they don't like how I treat them.
Well, partially anyway.

Okay, basically, it seems that the more I use an xHD on my PC, it becomes increasingly difficult to get it to work on it.  My current xHD, I typically have to plug/unplug for like 3 minutes before it actually works on my PC.  By "not works" I'm referring to it refusing to start up (plug into PC's USB port, the xHD clicks or sounds like it's trying to spin up, but fails, almost as if there's not enough power).  It's not a power issue, as plugging it into 2 USB ports seems to have no effect (and I can get it working on 1 USB port).
Initially, when I got the xHD new, it worked fine, but it seems to have slowly gotten worse over time.  Has happened with other xHDs I've had (starts off good, and gets worse over time) and occurred on my older computer.
It's not the xHD degrading either, as it works fine on other PCs, and fine on my netbook (just plug it in and it works).

Very odd - can't figure this one out >_>