I currently have the ancient AMD Athlon 64 x2 5200+. I've been looking to upgrade my CPU knowing I will have to replace my ASUS M2N32 SLI Deluxe motherboard. I have been looking at the AMD Phenom II X4 940 Black Edition Processor. I am not a wiz at this stuff so if anyone has any advice for me, it is greatly appreciated.
Newegg has a biostar TA790GXE for $99.99 shipped that will work with your old ddr2, and is loaded with features. Or you can go with an asus model for $18 more, as it doesn't come with free shipping. You may want to backup your files first, as these boards have an amd chipset, which may require you to format the drive.