Similar problem as Mike-H777
I have two 512 (original) sticks. I went to add an additional two 1 gb sticks (not recognized). The mobo user manual says that I did it right. The system info page recognizes the 3 gb of physical ram, but the available ram is less than 1 gb. If I remove original sticks, no boot. I tried moving the sticks around and reinstalling them, no go without original sticks. Boot up counts only the original memory sticks. I added DDR 400 with 184 pins, just like original sticks. I just purchased the 1 gb sticks non-retail.
