USB Portable Hard Drive not showing in Vista

Hello,

I connected a new 500G portable hard drive to a front USB port on my HP PC (with an AMD Phenom X4 quad core processor), running Windows Vista Home Premium. Windows showed a pop up saying that the driver software was being installed, then said: USB Device installed. The software for the device was successfully installed and it's ready to use.

However when I looked for the drive in Windows Explorer it wasn't there. I've read through this forum, and using information I've gathered I accessed Computer Management on my PC, in Storage/Disk Management - at the top it only shows drive C: and factory image drive D: but below that, where Disk 0 is allocated to drives C: & D: it Shows Disk 1, unknown, not initialized. Assuming this is the drive in question I attempted to initialize the disk, but then get the error INCORRECT FUNCTION.

I have no idea what to do at this point. I have updated Windows, updated the Bios, checked for newer device drivers, etc. If the Drive hasn't been assigned a letter, there seems to be no way to reassign or partition it without initializing it, which I'm not being allowed to do.

Thanks for any help you might be able to give.