AMD 4200+ cpu upgrade -Help Please

Nope no better option.

You may want to verify compatibility with the motherboard if you can. The socket will be the same, so the chip will slide in. However, some of the older x2 chips use 65w TDP's and the 6000 uses a 125w TDP. This could mean compatibility problems if they gave you a trashy mobo since the new chip will draw a lot more juice and dissipate more heat.

If your computer is socket 939 then you can't really upgrade it as a 4200X2 will be as good as it gets (o.k there are 4800s but they cost an arm and a leg now). If you have DDR Ram, then it's a socket 939, but if the RAM is DDR2, then it's at least an AM2 board. Anyway you're going to have to go to the HP website and see the CPU support for your particular model. I doubt you will be able to do much better than an Athlon 6000+ without a hacked BIOS, but check the HP website to be sure. Also, there are currently 3 versions of the Athlon 6000+. There are two Windsor models with the first one being 125W and the second being 95W. The latter is preferable. The third version is the Brisbane model.

Upgraded a similiar model with an Athlon 5800+ X2 brisbane 65nm cpu. Draws about the same power as teh old 4200 did, big wirthwhile jump in speed, processor was like $50.

Check motherboard specs the one I had was an OEM Asus.

939 was produced in x2 up to 4800+2.4ghz opteron 185 2.6ghz and FX60 2.6ghz unlocked multiplier.

Weird, cording to wikipedia you're right, but I don't remember being able to find any when I was looking to upgrade my old rig.