Tell it to run or it's grounded...
Whew, we all wish that would work.
First, I'm not really on the page where you remove a 512 module and replace it with a 1 Gig module, why would you do this? To get to 1 Gig capacity you just put another 512 module in the vacant slot. It costs half as much. Dual Channel Ram is motherboard dependent. I don't recognize your board number. So I can't tell you if the darn thing will run in a dual channel mode. What I'm certain of is; in a dual channel configuration the clock frequency is half the rated speed of the modules. So, if you read the clock frequency of a dual channel PC3200 400MHz system it will be 200MHz. Please, do yourself a favor, download the manual to the Mobo in question, and give it a go. RAM modules are generally a plug and play situation, IF YOU FOLLOW THE RULES. Are the chips in the right slots? are they compatible with this board? Is the module defective? Does this board require intervention in the BIOS to add RAM (Most don't but, I don't want to deal in absolutes). These are the possible solutions, but you still have to do the research.