If the drive has got a drive letter in (My Computer or) Windows Explorer, say it becomes f:, open f: by clicking it and copy the files around as you wish, just like you would on the normal hard disk.
You might need to take ownership of the folders and files on the hard disk first. http://www.vistax64.com/tutorials/67717-take-ownership-file.html tells how to do it in Vista (that's quite different from the way it's in XP).
Hope this helps.
My daughters gateway laptop died,I took the hard drive out and put it into a 2.5,usb exturnal hard drive.The old computer had Windows XP,the new computer has Vista.The exturnal hd has music,(I Tunes),Photo's, and Doc's.My question is, once I have the ext.hd identified on the new computer,what do I actully have to do to find the stuff I want to transfer? I have never done this before, and just need a little guidance...All help is appreciated.W