I just ran across a deal on a Dell 8400 that I considered too good to pass up. I presently have a Dell 8300. (The 8400 has a 3.4GHz processer vs a 2.8GHZ n the 8300, DDR2 memory vs DDR, PCI-e vs AGP....) Can I just swap the harddrive that's in the 8300 over to the 8400? The 8400 came with a 40GB hdd. The 8300 has a 120GB hdd, plus it has pictures, programs, short cuts, etc., etc., etc... on it that I'd like to keep using.