I have a custom built 1.4 P4 on a Intel D850GB motherboard where I tried to upgrade the memory with ddr memory but found out it only takes rdram but when I reinserted the old memory (4x64mb rdram) the system board beeped three times so I purchased 1gb of rdram and got the same response but when I only put the memory in the first rimm will not beep but now I get no video. Do I need a new motherboard or new video card? Also on the mother there are four diagnostic light with the first is amber and three green which means reserved???? HELP.

Seems RD ram is a little bit "picky" about installation... I think this would be a start. There may be other issues

Desktop Boards - RDRAM* Memory Installation Requirements

I installed four sticks of 256mb rdram and I would get three beeps from the motherboard but when I install just two it works fine but I still don't have video.

Yessir--did you read that link?
RD Ram has to be installed in a certain order for it to work right. The link is to the directions.