That is a toughie. Don't take me personal or anything. Just throwing some thoughts.
Sounds like you got the dx2200 already... Right? It is pretty outdated. You will have to look to see if the motherboard has a CPU power plug, if it does then you should be in good shape to use a quad-core as long as you get a new PSU. 250W just won't cut it. 450 to 500W will do good. Might even go down to 400, but if you wanna fold, then 450 to 500 is better.
Now, the RAM is a different story. 667 Mhz is old, but still plenty fast enough for a 5 year. 2gs should get you by for a while. Depending how fast your son grows up...
The GPU should take care of most games. My son is 12 and has a machine with 2gs and he is playing everything under the sky without any problems. Of course, he has a 4870, but I don't think the 8800GTs are that far behind. Coming to folding, um... I don't know much about the RAM usage in folding. I fold, but I have 4gs. I tried my son's and it was bogging the machine, but that was cuz of the GPU using so much CPU power. So, I don't think it was a RAM issue. Actually, I know it was not a RAM issue cuz I remember looking and there was plenty left. Mind you, it folded just fine, but gaming and folding at the same time got me a hear full from my son.
So, all in all, if the motherboard is supported then you'll be ok. So, knocking on wood for ya!
Remember the second paragraph is not from experience. Just assumptions for reading and hearing from others. In fact, you might even be able to google and find people trying to upgrade a dx2200 to your specs. I'm looking now...
Ok, this is great specs for everything about a dx2200: http://h18000.www1.hp.com/products/quic ... 26_na.HTML
So, I guess the real question is the FSB. There are two 533 and 800 Mhz. If you get the 800 you most definitely won't have a with a Q6600 quad. 533, um, I don't know. I highly doubt it.
Wow! I didn't think I would go on and on, so I will stop and let you tell us more. Please, do let us know how it goes.
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