Question : Problem: Will NOT Pass POST or Enter BIOS

Working on a customer's pc, which is a Sony vaio vgc-RB50.  OS - XP Media Center 2005, P4 processor 640, 512 MB (2 x 256) pc3200 sdram, 250 gb sata.  I have tried everything that i can think of and wanted to see if any of u had seen anything similar.  Will not pass post, and if i try to enter bios, it claims it is entering but will just sit there for hours.  Have already tried swapping ram sticks.  Wanted to get some "experts" lol idea on if it is MB or cpu which is what i am guessing.  Please Help!

Answer : Problem: Will NOT Pass POST or Enter BIOS

Remove any components other than CPU ,ram, and video card. Try to enter the BIOS now.
 If it does,start adding back components one at a time.such as HArd drive, NIC, CD drives. restarting each time. When it hangs thats the troublesome component.
 A bad hard drive can cause this while the BIOS is trying to access its parameters. NIC s have been known to do this also.