Memory stick

Hi there, i have two 256mb memory on my pc which has two more empty slots and capacity for 4gb. I bought a 2gb memory stick compatible with my system, my question is, do i have to take the 256mb memory sticks out, or just add the 2gb one, cause I'll have then 2 1/2gb of memory, is that all right??
Thanks
Patrick

With my motherboard, for some reason, I originally had to add the RAM sticks in order of size from left to right, left being closest to the CPU heatsink. You should be alright though, just make sure they get put in really nice and snug. You may need to put a little pressure down so they pop in.