Vista no longer recognizes external hard drive

My WD Elements 1.5 TB USB 2.0 external hard drive is no longer being recognized by Vista. It will not appear in either the system tray or when I click Start>Computer.

Below are the specs for my desktop computer:

• Dell Studio XPS 435 MT
• Intel Core i7 CPU 920 @ 2.67GHz
• 8.0 GB RAM
• Vista Home Premium 64-bit
• 1 TB hard drive
• Dual Dell 2408WFP Digital monitors
• ATI Radeon HD4670 video card 512 MB (one card only)
• All my drivers are updated (using Microsoft Device Manager)

When I plug the WD hard drive into my computer nothing happens, even if I give it 5 or more minutes to try to find it. When I plug this same external hard drive into my Windows 7 laptop, it is recognized quickly, leading me to believe the hard drive itself is fine.

I unsuccessfully tried to access this drive on my desktop computer though “Computer Management” by: Start>R-click Computer>Manage>Disk Management. There I see “Disk 0,” which includes my C and D drives, but nothing else.

When I plug the external hard drive into the computer’s USB port, I hear my computer make the normal “ding” that accompanies the plugging of an external device. Also, the external hard drive begins to hum.
I recently ran CCcleaner and don’t know if that was the source of my problem. I would try a System Restore, but that function has not worked on my computer for a long time.

Any advice is appreciated.
Don

Try this, see if it makes a difference: USB DEVICES - How to delete all (resolves some USB problems)

Thanks, Ztruker, for the lead. I decided to give my system one more shot at recognizing my WD external hard drive prior to making any changes. Amazingly, it recognized it this time. I did not do anything different. There was no letter defined for that drive once it appeared, but I solved that by Start>r-click Computer>Manage>Disk Management>r-click on the drive that now shows>change drive letter. Vista never fails to amaze me. I would have upgraded to Windows 8, but that does not seem to be a raging success either. I'm hoping Windows 9 will be better.

Thanks again for you advice.

Don