hey guys i have a compaq presario 5000. It takes pc100 memory and is supposed to have a max memory of 512. I bought one 256 stick from archmemory which works great but I bought some 256mb pc100 sticks off of ebay and none of them will work in my computer. I also bought a stick of pc133 which i have hear is backwards compatable with pc100 machines and that didn't work either. Did I miss something or did i just get bad ram modules?