SATA HDD

on whether you want to keep your existing data or not
If you do then you will need to make an image of your existing drive, then fit the new drive and copy the image to the new drive.
There are a few other issues as well, you need a motherboard that supports sata of course, and you will most like need to load drivers for the sata drive before it work, so even if you have imaged your disk you might still need to run the windows installation disk to "repair" the installation and install sata drivers
If you want to do a clean install of windows then just fit the new drive and boot from the windows disk, you can create the partition and format it from the setup process

First, you'll need to find out if your computer is able to accept a SATA drive. Is there a SATA interface (where you plug in SATA data cables) and a SATA power supply (plug)? If not, adapters can be purchased, but that's not always the best solution because of possible BIOS issues. If your system is not SATA capable, I would buy PATA instead.

Second, assuming you do have a way to plug the drive in, you'll need to find drivers to run it before the OS can be loaded on it.

Third, do you have an installation CD to install the OS and get it up and running before you copy your data files from the old hard drive? Yes, you can probably clone the old hard drive. But, why bring all your old problems into the picture? When you swap HDD's, it's a good time to start fresh.

Once you have answered those questions, you can get down to business. However, I want to caution you that if you don't know what you're doing, don't even attempt the swap. Take it to a PRO. Improper installation can cause serious damage to the system and possibly render it unusable.