For my system i started out with 512(256x2)MB of PC4000 DDR500 RAM. The sticks are one sided and the company is PQI. I wanst the one who initially bought the RAM so PQI wasnt my choice. But I recently got the money to upgrade my RAM so i bought a stick of 512 PC4000 DDR500 from Corsair. When i try and mix the RAM together though my system wont boot. The RAM timings are the same and i looked at my mobo manual for the RAM configurations. The stick of corsair is double sided and my other sticks are one sided. So it gives me a guide to where i should place the sticks and what speed to set my RAM in my BIOS. After i do all that it doesnt boot. My MOBO is a ASUS K8N-E NF3 with an AMD 3200+ ~2.2ghz. Any suggestions besides buying new RAM? Any help is appreciated.