Windows just doesn't go freezing up for no reason. It's got to be something. You basically replaced all of the hardware. Correct? Please list your specs.
I recently read a post by which someone else was trying to help anyone with random freezeups. After much troubleshooting and money spent, they found it all boiled down to the their mouse going bad. Have you tried a new mouse?
Ive used the mouse to build my buds pc with. Installing windows and ect. Hasn't locked up on his.