What is need for a computer to POST?

I know the motherboard is needed, and the video card, but is the cpu and ram needed for the computer to just turn on to bios?

You need a motherboard, video card, CPU, and memory to pass POST. You'll need a keyboard to enter into BIOS.

A computer will not even turn on without a CPU.

You need a motherboard, video card, CPU, and memory to pass POST. You'll need a keyboard to enter into BIOS.

A computer will not even turn on without a CPU.

XaosII

As a clarification to the above - If your Mobo has an onboard video controller, you won't need an actual video card; just the fore-mentioned stuff.

Just never turn on a computer without a processor in the motherboard. "Fun stuff" will happen.