I work with computers, and a hard drive that cannot be seen, given the circumstances of failure in the opening post, is usually a dead 'un. I'm betting that substituting another drive to see what happens would confirm it - and would save a lot of time.

It certainly isn't a corrupted driver, because the drive won't show at boot - it doesn't require a driver for that! It's also very unlikely to be a virus, because that would kill the motherboard.

It is unlikely to be a power supply problem, either.

At one time I'd have agreed that something else could be the problem, but hard drives are becoming less reliable as prices tumble and capacity soars.

I've got a box full of drives that have gone the same way. I only hang on to them because I can occasionally retrieve the info off another drive by using bits from an identical one with a different fault.

Sometimes it's the spin motor, sometimes it's the controller card, and occasionally it's the voice coil. The voice coil (head arm actuator) is the only part I shy away from fiddling with...!

My earlier post did suggest you may get lucky, but in my experience I doubt it.

I'll even go so far as to suggest a case fan may have failed, causing the drive to overheat... for future reference, download a little programme called 'SpeedFan' - it's free, and can be used to monitor temperatures, voltages and fan speeds (there's a surprise!).