It's a Dell computer and I tested the harddrive that it came with a small 6 gig and I have a 40 gig maxtor that I want to replace it with as I believe the 6 gig is only a 5400 rpm and the maxtor is a 7200 rpm, but it will not take for some reason, I know with the Dells and Compaq's they are a little harder to do things with as they make all thier own components but it is possible. Like I can have the 6 gig as master and the 40 as a slave but that is not what I want!! can anyone explain the process on how to switch this so I can have 40 gig as master and 6 gig out? Thanks, For any help you can be with this issue! Appreciate it all