(Is there any way to find its exact model?,I don`t have its box.)
It`s written on the installation CD:
GIGABYE 8 sigma series.
intell 915 series.
What kind of GIGABYTE motherboard can it be?
Then,
I want to know the max CPU,RAM,VGA... that it can support.
Where can I find these?
TANX

the best way to find out is pop open the case and google the numbers on the board untill it gives you a specific motherboard. then if you look up that model on newegg.com or something it should give you the specs on it.