Beeps and won't power up with new ram

[s37d]

I have an old 800 mhz celeron HP computer. It has 2 sticks of 64mb pc100 ram and I ordered 2 sticks of 256mb pc100 ram to replace them. I installed the 256mb sticks and it beeps and won't power up. Is 256mb just too much for each slot, and might I have to go down to 128mb sticks? Thanks

Here's the motherboard: Motherboard Specifications, Trigem Cognac*

 

[Nukem]

that's what it sounds like to me... the mobo can only handle a certain amount of ram... and it looks like HP says 256 only...