1. Get two matching drives - size and MFG
2. Install drives.
3. Insert Windows CD
4. Windows will start to load and at the bottom of the screen it will say press f6 to load Raid drivers. or something like that
5. when it tells you to, insert disk (floppy) with RADI drivers on it. These disks come with the Motherboard.
6. select Raid 1 (mirror)
7. Continue with windows load as normal
The steps may not be exact, but the main point is to load the drivers BEFORE windows is on one drive. Windows will not copy itself to the other drive.
I had a few issues when did this for the first time, but don't worry, its a simple operation once you get things going.