My hard disk fell out of my hand to the ground and has stopped working. If I plug it into the computer it says unallocated space – what can I do?
if it is hardware problem software will not help. if above solutions do not work. try to connect to another pc, mac, linux.
Try using the below tool -
External HDDs are very prone to shakes and movements.Do you hear any clicking sounds while it's powered up ? If yes,if you get chance to view files,quickly make a backup of it.
May be a physical damage occur to your hard drive, if it shows only unallocated space and not making a noise then using third party data recovery tools you can recover your data your self.
Use windows data recovery software from http://www.freedatarecoverysoftware.org
It's not free but a trial version. There are other freeware that might be worth trying. Recuva, http://www.piriform.com/recuva, is the one everybody recommends, but you might need to try a more advanced program like TestDisk, http://www.cgsecurity.org/wiki/TestDisk, to really get an idea if its recoverable. Chkdsk might be necessary if they don't work and as I said the real expert, http://wiki.lunarsoft.net/wiki/Data_Recovery, strongly advised against using chkdsk and has other ideas to do instead.
This is the best article I've ever read on the subject:
If you have a computer friend who is an expert, ask if they can help you go through it. Otherwise try chkdsk as suggested in the makeusof article. (I know the article tells you not to use chkdsk):