Windows 7 - My Computer crashes when attempting to access any portable device.

I'm not 100% where to put this but I have a peculiar problem with my portable hard drive. None of them work on my computer (with Windows 7 64bit). It is no problem with my hard drives as they work perfectly well and instantly on my Notebook that holds Windows XP.

The interesting thing that comes with them is that when plugged in, they do peculiar things to the system. The drive sometimes shows up but is inaccessible and crashes when I try and access it. Scanning it for errors also sits in limbo and it being plugged in has even led to it preventing windows updates from backing up system restore. Other times it doesn't show up at all and when I disconnect the drive it asks me whether or not I want to format it.

In several hours I managed to access the portable hard drive once only to be blocked by the absurd "discovering items" glitch that renders copying files impossible.

Yet about a week or so ago it was fine. It worked with no problems at all. I would pass on some hardware details but my computer is tooling around restarting at the moment.

Try a System Restore to a point a week back or earlier, when everything was fine.

Also let us know whether you have installed any new software during this period, especially any security software.

I system restored back and it did not resolve it.

Additionally, I have no new security software installed and I already tried disabling it when accessing the harddrive. The only recent thing I installed was a Firefox addon which is involved in proxies and nothing else (I'm on my laptop and the name eludes me).

It is worth adding that all other devices work absolutely fine on my USB ports in my computer. They seem to merrily accept an old webcam that doesn't even work with Windows 7 properly for heaven's sake.