I have PC with 512 MB RAM installed (motherboard manufacture MICRO STAR, chipset P4M800), pc was running very slow so I decided to upgrade the ram. I installed CPU-Z and check the ram installed on the machine, also had a look at the stick installed. 512 MB PC 3200 400 MHz DDR but my mother supports 200 MHz and it was working ok. So I bought 2GB which I checked on manual that it support upto 2 GB Ram. So I installed 2GB PC 3200 400 MHz same as the old one, I plugged in both eventhough motherboard only support upto 2 GB but system spec only shows 512 (deducts 64 MB shared vga memory) I checked on CPU-Z, it detects both, slot 1 512 MB, slot 2 2048 MB, comparing screen for both slots, both the same, volt 2.5, frequency 166 MHz and 200MHz, only difference on those is 2gb ram shows under timings table 133MHz 166 MHz and 200MHz but 512 MB shows only 166MHz and 200MHz. I checked on Google and can't seems to figure out whats wrong with it. If I only plug in 2GB. Pc doesn't boot up like ram not working.With only 512 MB plugged in seems ok. Please help.