I have a Sony Vaio VGN-FZ290e laptop on which I recently changed CPU's. It came with a T5250. First I tried a T7100 and then a T5850. I've now got a T7700 which based on the Sony community forum moderator is an acceptable cpu upgrade. The problem is since I started the upgrade, my laptop will only recognize a single memory stick. I've got a pair of 1GB Qimonda sticks and a 2GB Qimonda stick. Prior to the upgrade I had 3 GB running. Now if I try the 2 GB with either 1 GB, the Bios only recognizes 1 GB. I've tried in slot A and B and vice versa with the same result so I don't think it's the motherboard. It's not the memory stick because I used Memtest on all combination of memory in the slots. The Bios version is Phoenix R1120J7. I'm running the single 2GB stick. Any idea whats wrong?