I have the same computer, and have done the hard drive upgrade. All you do is unscrew the bottom shell, there are four screws. Two are at the front, and two are behind the panel that the VGA port comes out of. Once you take the shell off, you'll see a perferated metal covering, which covers everything. I forget how many screws there are to take this off, 8 I think. Once you take that off, you'll see up at the front, centered, the carrier for the hard drive and optical drive. The hard drive is the top-most unit. I would recommend removing the RAM sticks at this point, so you have clearance for removing the hard drive. Now, unplug the IDE and power cable from the hard drive. You'll see 4 screws on the top of the carrier unit which the hard drive is in. Unscrew these, and pull the hard drive out. Thats it! If my directions are a little confusing, let me know and I can clarify.