Hello, recently I have purchased new RAM memory for a little extra oompf. My computer is an emachines t5212 ati radeon xpress 200 chipset and a D101GGC2 intel motherboard. The computer runs stock with 2x512mb (1gb) ddr2 sdram (533mhz/pc4200) in its only 2 available slots. I just recently purchased 2x1gb (2gb) ddr2 sdram (800mhz/pc6400) sticks to upgrade and when i remove both of the prior ram sticks (2x512mb (1gb) ddr2 sdram (533mhz/pc4200)) and replace them with the new ones (2x1gb (2gb) ddr2 sdram (800mhz/pc6400)), my computer will not boot up. I have tried this with 1 stick of the 800mhz/pc6400 ram. However, when i use a combination of 1 stick of 512 ddr2 sdram (533mhz/pc4200) with another of 1gb ddr2 sdram (800mhz/pc6400), it will boot up and detect the memory increase, i.e. (512mb). I was wondering if it was because of my mobo bus speed of 533mhz requires the 533mhz/pc4200 ram to be in, in order to boot, which would allow it to then further detect the 800mhz/pc6400 ram and then drop it to the required frequency? Is there a way that I could adjust my mobo to default at 800mhz so that I could use both of my 1gb 800mhz/pc6400 sticks and attain the 2gb memory that I wished for? Would this harm my computer? When researching my mobo, the 2 standard frequencies WERE indeed 800 and 533. Any help would be much appreciated. Thank you.