get your 256 ram and put it in the comp on its own and then turn the comp on. if it doesnt come on then the ram is probably screwed then put another stick in and if it still doesnt turn on the your motherboard or CPU it screwed. you can also buy info LED's which tell you if there is a problem with any thing in your computer. if you computer comes on and loads up then go start->run and type in dxdiag and it will tell you what your computer has.