Q: Without having hardware problems.
A: I assume that you are running Xp or Vista. Swapping the hard drive, if you are lucky, can be as simple as out with the old in with the new drive. But the more likely scenario is that you boot to the newly installed drive and promptly get a BSOD. This is due to what windows sees as an excessive amount of hardware changes. Possible solutions: 1) Repair the windows installation after swapping the drives 2) Clone the drive of the new computer to the Old drive 3) Use the Old drive as additional storage (i.e. Slave drive) Good Luck