disc mgmt & device mgr don't recognize external hdd

[adalgisa]

I just bought a WD 500gb Scorpio Black Advanced Format drive for a friend to use to back up documents. She has XP Pro on her computer, and rather than run WD's align utility I thought I'd format the new disk on my Windows 7 64 bit system.

I put the drive into an external enclosure & plugged it into the USB port. The enclosure doesn't have a separate AC cord, just gets power off the USB port.
The drive is not recognized in disk management, nor in device manager, when I look under the USB hub.

When I put a WD 750gb Scorpio Black AF drive that I'd already formatted and partitioned into the enclosure and plugged it in, at first it didn't show either. I went into device manager, usb hub properties, and looked at the power tab. The drive didn't show. I clicked refresh, and the drive appeared. This didn't work with the new drive, however.

Could there be something wrong with the drive? or is there something else I can try?

[EzyStvy]

I'm pretty sure the WD's align utility is only for drives over 1tb when used on an XP machine. So maybe it got hosed from the utility.

Take the USB part out of the mix and connect it directly to your mobo.

[kilgoretrout]

Does your enclosure come with a usb Y cable like this:

Amazon.com: Apricorn USB Power Adapter Y Cable AUSB-Y USB (Black/Grey): Electronics

One usb port is frequently not enough to power a hard drive which is why many no-power supply enclosures come with a Y cable to allow the device to draw power from two usb ports.

[adalgisa]

EzyStvy, I didn't run the Align utility on the drive. Just took it out of the anti-static envelope & popped it in the enclosure and hooked it up to my system.

KilgoreTrout, I took your suggestion and tried a different cable, one with a y-connector, but the drive still doesn't show up anywhere.

[glc]

Use standard SATA cables and install it internally in a desktop computer. If it's still not seen, RMA the drive.

[adalgisa]

Thanks for your help, folks. Before taking apart my system to test the drive in there, I tried again plugging it into my system with the usb enclosure; this time Windows said I needed to initialize the drive, or that it was unformatted - I can't remember which - the important thing was that Windows noticed the drive was there.

Can you recommend a good disk diagnostic I can run on the drive before returning it to the owner? Right now I'm assuming that it was my error, but maybe the disk is not totally reliable--?

[glc]

WD Diags, Windows version.