portable harddrive

I have a simpletech pininfarina portable hard drive it has worked great up
untill yesterday. I could access all my files on it with no problem.
I am running windows xp. I noticed that over the thanksgiving holiday my
computer did updating and shut down. I also installed a new HP wireless
printer on it this weekend. Since then it does dont show my portable drive,
i have uninstalled and reinstalled and it either says unrecognized or error
when installing.
I can take the portable hard drive and use it on my laptop which is running
vista just fine. But on my desktop with xp it doesnt called tech support for
the hard drive and they had no idea.
I even tried to uninstall the microsoft updates and that did not help.
Any ideas????