[SOLVED] CPU Replacement Help!

No. You can't swap an AMD CPU into an Intel compatible motherboard. To know what CPU you could possibly use, we need to know the make and model of the motherboard.

A full list of your components will help us determine if a CPU upgrade is even worthwhile for you.
 


I have a very old motherboard .. MSI 3664h
 


You not only have an old motherboard, it is an HP motherboard. That will limit what CPUs you can use.