Memory upgrade problems

Hello, I am running xp pro with an amd 1800(1.53 ghz) 768mb ddr 2100 and an abit KR7A 133 Raid mobo. I have one slot of memory availbable and decided to add another 256 of micron memory, I use micron and samsung. the problem is that after doing this windows halts the boot process at the screen just before the Windows Xp logo screen and stays that way, If I remove a stick of memory, any stick not necessarily the one I just put in, then every thing is fine. Any suggestions. Thank you.

 

Might want to do some checking as some mobos can be limited to a certain number of sticks with some ram types.

You are not mixing Unbuffered and Registered ram are you?

Mixing manufactors of ram can cause this also.

 

My mobo allows for 3gb of ram and the sticks are not mixed, they are all the same.