How Large of a PSU?

Sorry I lied, it is only a 600 Watt PSU and it is a Thermal Take.

Is 600 not enough?

600 is definitely enough.
The new memory could be causing problems, yes, but so could a million other things. Run some stability tests and see what they tell you.

What Thermaltake Series and model number?

Some of Thermaltake's low end models have very poor DC output quality (i.e. high electrical noise and ripple) that will cause random reboots, BSODs, random lockups, etc.

^ +1 like this psu > http://www.hardwaresecrets.com/article/Thermaltake-TR2-...
But honestly that setup should be ok as it wouldnt be pulling more than 350w tops (like with furmark), normally much less.

Make sure you are running the latest video drivers (not beta). Occasional shutdowns or system restarts happen primarily due to driver issues. Btw, you have a pretty good spec to handle windows 7. Its recommended you make your switch towards it.

Based on your description, it sounds like you were getting an issue before you replaced the bad RAM and only after adding the new RAM?

Remove the new RAM (two new sticks), only use the RAM you know was working, and try to run the PC that way. If it works then you know it's the new RAM.

600W is way way more than enough for your set up, but it should be a branded 600w, not the generic cheap 600w psu.
a branded 500w will even do handle your setup. usually the cheap psu has a shorter life. if it is not the videocard nor the memory maybe the psu.
but if you are running windows xp 32bit, i think the extra memory is the problem, do not put more than 4gb memory on a windows 32bit, it will cause problems.

600W is way way more than enough for your set up, but it should be a branded 600w, not the generic cheap 600w psu.
a branded 500w will even do handle your setup. usually the cheap psu has a shorter life. if it is not the videocard nor the memory maybe the psu.
but if you are running windows xp 32bit, i think the extra memory is the problem, do not put more than 4gb memory on a windowsXP 32bit, it will cause problems.

I woke up this morning, and the computer would not boot. I pushed the power button, only for the system to spin up (You could head the HDD's kicking in) but the system never came on. So I pulled the two sticks of memory out (naturally I had to pull the darn graphics card out to get at it) and the system came online just fine.

Do you think the memory is bad, or is Windows XP not able to handle the 4gb, is it causing a conflict? I know Windows XP 32bit can take 3GB of ram, but I put the 4th stick in and got another .25.

Suggestions?

I suggested what you just did above.

Windows can handle four gigs, but will only show around three and a quarter usable at most. Your memory is bad (again) if it boots up and works fine with it not in.

Return the new RAM. Make sure what you replace it with is similar to that which you have in. Make sure you memtest the stuff once you put it in.

thanks for the help, I appreciate it. Where would I find a mem test program?

http://memtest86.com/

Thanks. Memory is bad I am assuming, I can't boot to check the new memory, but I tried it without the video card with the old 2gb. worked fine.

Put the new 2gb in, and it wouldnt boot.

Put the graphics card back in with the old 2gb and it runs fine.

That's some bad memory. Is it a different type from your functioning sticks?

Nope, same GSkill memory I bought years ago when I built the computer.

The sticks of course look different because it appears they had changed the cooling part on the memory