Ram problem?

Hi All
I just purchased some new ram for my rather old pc. It has a p4 3.0 asus mobo 7800gs card.
The ram installed is corsair 2 sticks of 512 400mhz pc3200 ram.
I just installed two more sticks of 512 made by PNY. Other than different manufacturers it is exactly the same.
Now, when i turn on the pc the first time it gives one long beep followed by continuous short beeps. The screen is black and it will not boot.
Ok, at first of course thought the ram to be incompatable. While the pc is beeping i have to do a hard shut down to turn it off. I wait for about 5 to 10 seconds press the start button again and presto it starts? While it is booting up it tells me overclocking failed and will return to default settings? This happens every time. The first time i always get the beeping but the second time it always starts? It does prompt me to press either f1 to enter setup or f2 to return to default settings. I have not altered anything in the bios and have never overclocked my cpu?
Can anyone help me? This has got me stumped?
Thanks John.
My system
p4 3.0 running xp, 2gig of ram when it works
7800 gs card, mobo ASUS p4s800dx.

Hi r-manic
Yes the fsb numbers on all are 800. Also i did try the new ram on it's own and the pc turned on and ran just fine. No beeps etc.
Thanks John.