If you are replacing the original so you don't change the actual number of drives on the machine you might be OK. If you add the HD to an existing one then you might find all the drive letters change - and that's messy. bones -----Original Message----- From: jhb_airlines-bounce@xxxxxxxxxxxxx [mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Smith Sent: 13 July 2005 19:10 To: jhb_airlines@xxxxxxxxxxxxx Subject: [jhb_airlines] ot My wife has bought a second hand pc to replace her steam driven one.can I change the hd in the new machine for the one out of her old machine.old one is a athlon 1.2 the new one is a athlon 3600+ Tom