Well All Righty Then...... Captaincranky: 32 bit XP really only needs 2 GB to run well. Tedster: Read the Guides. Blind Dragon: Run it with 3 sticks. Captaincranky: It won't recognize the 4 GB of Ram. Other than that, you can try putting in 2 512MB sticks instead of the extra 2 1GB DIMMs. At least that way it will run in dual channel. It would tell you if it's the four DIMMs or the 4 GB that's giving you the problem. You've been helped. It doesn't seem that any of the answers agree with what you think you want to hear. "4 Gigabyte Fever", will pass believe me I had it once.