Check motherboard doesn't any led's on the front of the case come on.

yeah everything (lights pump fans and onboard LEDs) come on
and today i even caught 2 POSTs.... but the comp stayed on less than 10 seconds both times.

sound like a ram problem, usally your system won't beeps just system keep restarting. even if it the right type of ram some motherboards don't support ECC ram or have a problem supporting different brand for some reason try diffrent brand or take ram from different computer that use the same type of ram and swap see if system work, can't say it the video card because you saw it trying to post check cpu next. Knowing that you are using water cooling next question is did you let water run though the tubes and the pump fill up the radiators back in to the water block to the pump first before installing the cpu.(If you didn't more likely you damaged the cpu amd 64 get very hot quick and water take 1-2 mins to flow though the system right and you will still see video but you damage some of the transistors in your cpu which is why it will come on but as soon as it try to post it will shutoff.)

yeah i let the water loop fill properly b4 starting components but that WAS ages ago. and ive been running the same ram forever and when i bought it i asked OCZ guys if it liked the mobo i have... and they said it does... and it overclocks to about 270Mhz in it.

but today its been booting up and staying on but only after a few tries at booting it up.

Hi calmchaos,
POST failure can be ANY of the following:
> PSU
> RAM
>keyboard
> CPU
> MOBO
> video
You don't have enough info for us to help you..so.. you need to do a basic & complete troubleshooting of ALL you hardware & get back to us with more info.
RGPHNX

i kno im usually the person helping people and its frustrating to not get enough information.
But now my computer is working fine for some reason and it even let me overclock it to a nice point of stability.
I didnt change anything.... but now it works... i dont undertsand it but im not going to complain.