Well, you can try, but if the one with the old hard drive is a 40 pin cable you'll want to go buy a new 80 pin cable. So trying with the old cable just to see if it works shouldn't hurt anything, the hard drive will just run in a slower mode. If the old cable works then go get a 80 pin cable appropriate for your HD speed.

A+ Certified PC Tech Guy/Seitentaisei