Motherboards will not power up!!!

I have a compaq presario 5311, with 512meg of ram, 1.2Ghz, 40gig hdd and windows xp home. My problem is the the motherboard will not power up. The power supply comes on and the network card lights up, but harddrive and cdrom will not power up, I took out the memory power up not even one sound to let me the memory was out of the computer, I put the memory back in and still no sound. The memory does work in other computer and so does the cdrom and harddrive. What is wrong with my motherboard? Replace or Keep?

Thinks,

John