External HDD problems
 

Friend gave me his external HDD and it doesn't work. When you plug it in, you can see it in device manager but not under the disk manager. Tried different USB ports, different PCs, different USB cables that I know work and still nothing. I'm guessing its dead at this point and I can reformat the drive, but any other things I should try?

Have you tried installing drivers from the manufacturer's website?

Yup
Tried plugging it in again and found it and can open it but crashes when I try to do anything.

I'm sure you've already tried it, but I have a couple of plug-in devices that will only work when I boot the PC with them already attached. Pluging them in after boot; everything always looks normal as in 'Device Recognised' blah blah.....but no life, and that's with all the latest drivers.

Yup tried that too.
Weird. I've been noticing a lot of harddrive failures the past 2 years

you said you can reformat the drive, does it still do this after a reformat? Have you tried it on other computers?

Wirelessly posted (Blackberry 8800: Opera/9.50 (J2ME/MIDP; Opera Mini/4.0.10031/308; U; en))

Nop. Fails when I try to reformat it.
Looks like at this point its going to be a RMA

Recently several external USB drives have a two-headed USB cable, one for data+power, the other just for power. Recommended on some computers you need BOTH plugged in to get adequate power.

If you're seeing it in Device Manager, then you're seeing the USB --> SATA (or IDE) controller card. Seeing the disk in Disk Management is where you actually see the drive.

I concur that (if, indeed, it is operational) it sounds like the drive isn't getting enough power to spin up.

Based on experience with a lot of these, the two possibilities have been mentioned above - the drive may have failed mechanically or it may not be getting enough power. The symptoms are the same in both cases.

So try to fix the power problem first. Either a double headed USB cable or a separate power input might be required, depending on the brand. Try it on more than one laptop and be sure the USB port is powered (most are on recent machines, but three or four years ago, not all USB ports provided power)

Also, if the laptop is running on batteries, the power management system in most laptops can limit or shut off the power to the USB ports, so do a test with a fully charged laptop that is plugged in to the mains. You can also disable this power management function in control panel/system/hardware/device manager then go into properties for each USB root hub you see and choose the power tab.

If it's worth the trouble, you can buy a 3.5in to IDE or SATA adapter which would let you connect the drive to a desktop machine. If you need to get data off, or you need to be absolutely certain it is dead, this is a definitive test - but you need to get the drive out of the case, buy the adapter, open up your desktop and know enough about the insides to be able to make the connection. If the only copy of your important PowerPoint presentation is on an apparently dead drive, it can be worth trying.

operating system
 

I have several external drives and arrays. I encountered a problem with
one drive simliar to your problem, only to find that it is not supported under windows vista. After looking at the specs of the other drives, I find that only two drives support windows vista. I don't have the reason available(there is a reason), but under windows xp, there is no problem. I didn't expect this to be a problem, but there you go...

2 op my newer external HDs work well with XP but would not work with Vista. At one point with the SP1 update, they worked for couple of power-ups. Never showed up on explorer window again since. Tried to delete INFCACHE file deal, to no avail :td:
I think Vista sucks.

It would have been okay if it just didn't work with the drives, but it seemed like it was working with Vista and I ultimately had 2 drives corrupted until I realized there was a problem. What was even worse - one array with 1.1Tb of movies and stuff seemed to be working with Vista, but during the transfer, it halted and wound up corrupting the entire array. Could not recover the drive, but I had a backup. And to top it off, Vista is much slower for transfering files. Only after this, did I look into the specifications. I didn't think there would be a difference between Vista and Xp.