Ok well from our conversation on AIM it seems like the 1 Gb stick is busted, and 2 of your 4 RAM slots are either disabled from a hardware level or disabled in the BIOS. Thats why it wont boot with the 1 Gb stick only, and if you use the 2 x 256 Mb and 1 Gb then it boots but it only recognizes the 256. The 256 works, the 1 Gb is busted and teh other 256 is in a disabled or broken RAM slot. I dunno if this is actualy whats going on though lol.