Need help on booting up old computer with Iwill motherboard model P55XB2 V 1.2 and Diamond Multimedia video card model Stealth 3D 2000 V2.04. Any help will be greatly appreciated.

Is this a board that you are trying to set up or is it a board that you have been useing? Have you added either new DIMM or SIMM memory modules, if you have, make sure they are seated correctly, Pull out the memory sticks and reseat them! It could be your vga card thats causing the problem, if you have another video card try useing it!

These are the symptoms of either bad memory stick or not seated correctly! Remember that SIMM modules are installed in pairs (2 Sticks) and Dimms can be installed 1 module at a time!
1. Two DIMM (DIMM 0, DIMM 1) socket—support 3.3V Unbuffered Synchronous DRAM (SDRAM).
Each DIMM memory size can be 8/16/32/64/128 MByte. The maximum memory is 256 MByte that is the Intel 82430TX chipset maximum support.
2. Four SIMM socket (Bank 0, Bank 1)—support Fast Page and EDO DRAM.
These four SIMM sockets devide into two Bank by each two SIMM socket. Each two SIMM in the same Bank must be the same memory size and type, the Fast Page and EDO DRAM can not be in the same Bank.
The above info was taken from the manual!