computer specs

Form the mannual or from searching the internet and finding some mathing web sites to your motherboard manufacturer

Apart from the above device manager thing , in any case you need to know the fsb, miulitplierm vcore voltage of processor get a small software called cpu-z. Also you can know your chipset manafacturer, north bridge and south bridge controller, frequncy and timings of RAM. Core of processor and technology used (90nm,130nm) etc.