Computer refuses to recognize external HDD

Ok I have a 200 GB WD HDD in a Vantec NexStar 2 external HDD enclosure which has been used in this fashion for months with no problems until today. Eariler today it worked fine but it stopped working later on. By not working I mean I can not access it even when I type L: into run nor does it show up in My Computer. When I do turn it on it shows up fine in the device manager and there are no other warnings. I have tried restarting it to no avail. I also plugged it into another computer and when I turned it on it made the "a USB device has been plugged in" sound but didn't show up in My Computer and no errors are shown in the device manager. I've taken the HDD out of the enclosure and reconnected it and tried different USB ports. Any ideas on what is wrong?

 

What operating system, plz?

 

Windows XP Home. I plugged the HDD in as a slave and it shows in the device manager with no errors but I cannot access it. I tried a different HDD in the enclosure and it works fine.

 

With the drive plugged in...

Goto control panel> admin tools> computer management and select disk management.
Check there for a drive that does not have a letter, then click on the drive and assign a letter.

Might be there if Windows is detecting it correctly...

 

It doesn't show up the disk management.

 

Ok, back up you "plugged it is as slave" So you changed the drive's jumpers?
If so most external cases you have to set the drive as master or single.
Where does it show in device manager? as what?

 

It shows the HDD under HDDs in the device manager though the jumper shouldn't be the problem since the HDD was working fine for months in the enclosure and the only time I have touched the jumper was when I tested it as a slave but I changed it back to what it was when I put it back in the enclosure. I have uploaded two screen shots of the device manager. One when the HDD is off and one when it is on.

 

Seems to me that if it isn't accessible in My Computer and doesn't show up anywhere except the device manager, even when slaved, the HD is failing. Go to the WD web site and grab their bootable diagnostic tool. Create the floppy (or CD from .ISO if you have no floppy drive), power down, connect the drive in question as the one and only master/single drive, and boot to the diag and run the extended/advanced test... that'll tell you for sure what's up. Hopefully it's less than 3 years old so you can get a warranty replacement... good luck!

hd2k

 

Well I ran both the quick test and the full test and here are the results...

Test Option: QUICK TEST
Model Number: WDC WD2000JB-00GVC0
Unit Serial Number: WD-WCAL83168328
Firmware Number: 08.02D08
Capacity: 200.05 GB
SMART Status: PASS
Test Result: PASS
Test Time: 22:59:42, June 14, 2007

Test Option: EXTENDED TEST
Model Number: WDC WD2000JB-00GVC0
Unit Serial Number: WD-WCAL83168328
Firmware Number: 08.02D08
Capacity: 200.05 GB
SMART Status: PASS
Test Result: PASS
Test Time: 01:01:25, June 15, 2007

 

Have you tweaked services.msc? Scanned for hardware changes? I'd bet you've rebooted.
Uninstall it from device manager and then reconnect it, I believe Windows is seeing it, but it isn't where Windows thinks it should be..
Bug

 

I put my HDD in a as a slave last night in order to run the Data Lifeguard diagnostics and I decided to check to see if it was showing up in disk management and it is...only it says it that all the space is unallocated. What are the names of some good data recovery programs?