Windows 7: Problem to connect WD Passport (USB)

Hello,

My Windows 7 don't recognized my 2.5" external USB WD Passport. The HDD runs under the same System with XP or Vista but not at my new 64Bit Windows 7. The status LED is on, but then happens nothing, sometimes he wants to install the driver, but that doesn't work.
I was trying to fix the problem with searching at google and this forum but nothing really helps me:

• I install the newest BIOS Version (V1.6 at an Asrock 4Core1600Twins-P35)
• I have the newest Intel chipset drivers (9.1.1.1020)
• I pluged all other usb devices out and changed the port
• i tested it with an Y-cable in case of low power

my other usb hdd (WD 3,5") works on the same ports very well. I already tested the WD Passport on my notebook to see if it's an hdd problem, but the WD works very well on my notebook(XP).

Do you have any advice for me?

Thanks in advance!

You plugging into USB port on a hub, or on the front of your case, or on the rear of your case?

I've seen situations where this really DOES make a difference.

I have an external 2.5" drive, and when I use the y-connector on a hub, Windows doesn't see the drive, but when I plug the connector into two USB ports on the case, it DOES.

I plugged it everywhere: on the front, on the rear and only for testing with an usb hub together. At this moment I consider to buy an cheap pci-usb card for my WD HDD.