My external hard drive is coming up unnallocated under computer management all of the sudden.
I recently upgraded my laptop to windows 7 from vista, I never had any problems with vista. It was working fine in windows 7 at first, no problems, but then all the sudden it dissapeared from my computer like it wasnt even plugged in, even though it made the usb sound when i unplugged it. So i checked computer management and there it was as unallocated. It's a 250gb usb hard drive. I know i probly gotta re-partition it/re-format etc to get it up and running again. Anyone know how i can get the data off before hand or is it gone for good?

Try connecting it to a different computer, see if it works there. If not then it may very well be dead and there may be no way to get anything off it.

Do you leave the external drive plugged in and turned on all the time? Have you tried booting with the drive already connected and turned on?

I leave it plugged in all the time, have unplugged it a few times. Will try another computer, just found a program "data recovery wizard" might give that a try.

If you can't see the hard drive then you can't run any kind of data recovery program, at least none I'm aware of.

You could also remove the hard drive from the external enclosure and mount it as a 2nd drive in your computer or put it in a different enclosure. Often it's the external drive electronics that gets messed up while the hard drive itself is okay.

Only got my laptop with me few next few months so cant really add it as a second drive. The program i mentioned aboce has worked anyway. It found pretty much everything, even stuff i deleted ages back so what able to back it up