External HDD problem

I have an external 2.5 HDD which is a 120gb that is powered up by USB only. It used to work all the time but just today, when I plugged it into my laptop USB, it powers up... and then nothing. Nothing shows up in My Computer. I bought another cheap external enclosure in case that was the problem but that still gave me the same problem. So what hope is there if I buy a 2.5 to 3.5 adapter and putting it into my desktop PC to try and salvage whatever I could?

I'd say you've got a chance to get it working.  USB is generally made of AIDS and fail, so direct connection is to way to go.

If you want a working adapter, mine looks like this one: http://www.thetechgeek.com/images/product_photos/sabrent_appide23.gif

>>1
if you use cheap enclosures, what probably happened was you jostled it wrong, and now the hard drive is fucked.