2nd SATA drive's files are inaccessible

Hello,

I'm really hoping someone here can help (and thanks, in advance, for your time).

Here's the situation:

I just got a new HP with Win7. I added a SATA HD from my old computer (that was running XP). The 2nd drive is recognized as E:, and I can see all the files on it.

But when I try to open most files, I get an error saying I don't have permission to open the file, and the instruction to contact the owner or administrator to change permissions.

If I try to copy/move some files from the old drive to the new drive, I'll get a similar error.

I installed an application and tried to access data on the old drive and, again, I get an error that the file cannot be opened, "Cause: Access permission denied. File may be marked Read only or locked (13)"

I'm stumped.

Any help you can provide would be HUGELY appreciated (this is my wife's computer and I'll be a big hero if I can fix it ;-) )

Thanks again.