My previous computer's power supply and motherboard died, I got the hard drive out and connected it to my new computer via USB.  I'm able to open all of the folders except one - documents and settings/"username".  The hard drive keeps running and I get no error message and end up cutting the power to the hard drive.  I'm able to open the other username folders.  The new computer is running Vista.Right-click on the folder and go to Properties.  What does it SAY?I'm not at the computer now, but I remember it said 0 memory USED, but there should be stuff in there.It may be possible that it was corrupted when the PSU went out.

Have you tried accessing any folders that are within that folder?  For example, in the address bar, try accessing C:\Documents and Settings\[username]\Desktop.  Try this out when you get home and see if it works.  If not, you may want to try a recovery program such as Recuva (it's free).Taking ownership of the folder might work.Dusty's advice is worth to try, however the link is for XP.
For Vista:
http://www.mydigitallife.info/2007/05/25/how-to-take-ownership-and-grant-permissions-in-windows-vista/
or for permanent right click item:
http://www.winmatrix.com/forums/index.php?showtopic=13157
Quote from: Broni

Dusty's advice is worth to try, however the link is for XP.

I was able to open only one the desktop sub-folder

Taking ownership didn't work

I took ownership of "username" folder.