GA-EP45-DS4 freezing. RAM problems?

hello, i just purchased a new system:
mobo: GA-EP45-DS4
CPU: Q9450
GPU: 9800GXT black edition
RAM: OCZ 4096MB, DDRII800, Kit Of 2, CL 4-4-4-15, Titanium (OCZ2T800C44GK)
PSU: OCZ 600w StealthXStream

well, i was trying to install a new OS.
started with XP 32bit, it freezed (system running, but screen shows everything stopped..) at install when showing 34 minutes left..
when trying to install Vista 64bit, it freezed randomly.

I've searched all over the internet, but haven't really found a solution for my problem.. is it mainboard/RAM incompatibility? Should i buy a new RAM?

well.. test was running about a minute and it stopped.
second time i booted up the test, it lasted for 3 seconds

It is probably bad ram, it is more unusual for a mobo to be bad.
Run memtest with each stick in the first slot, then the second slot...etc.
You are trying to find out if it is the mobo, or the ram.

However, since no ram seems to work, either the mobo is bad, and needs replacing, or the ram is not compatible.
The OCZ ram configurator does not seem to have been updated much, and does not have your mobo on it.
Corsair, Kingston, and Patriot have configurators, so you could check there to see what they have for supported ram.

What to do now?
If you can't identify which is bad, I think I would replace the ram with modules that the Corsair configurator suggests. Don't look for modules with low timings, since they will need higher voltage adjustments to run at that level. You want ram that runs out of the box at default SPD levels on your mobo.

yea, everything is at stock (default mainboard settings) except memory - 2.1V (1.8 default) and 4,4,4,15 (5,5,5,18), i tried to change these values.. leave it unchanged etc.
I will return PC to reseller, so they will test it and install OS on it. I am trying to get this PC to work for 3 days, and i am really tired of this.