Currently i have an amd athlon 64 3800+ single core at 2.4 ghz and i want to upgrade:
MBO : LENOVO (CPU 1)
Chipset Vendor ATI
Chipset Model Radeon X1250
AMD Athlon 64 Processor 3800+
Socket AM2 (940)
4gb Ram DDr2 200 Mhz
What do you want the upgraded system to run? You can find a used Core 2 Duo system at 2.6 gig + for close to $100 which would probably be a lot more worth it than upgrading your system. You may even be able to re-use the RAM.