Sounds like an old PC.... in need of UPGRADING lol.

Is that fan OK? When you PC is off, move the fan with your fingure. Does is spin freely or is it stiff?

As long as the BIOS is the only problem onboard, then there's no risk in it hurting your graphics card.

Hmm but how do i know if the bios is the only problem onboard or not?

Fan does spin freely but stops quickly.

I wouldn't have thought there was much chance of it, but saying that, from what you have said, that PC doesn't seem to have much going. External fan failed, CPU fan sounds like it's about to seize and you have a BIOS problem... nice!

Yep doesnt seem like it does it

Im guessing there is definitely a part that needs replacing, but which part would this be or is it multiple parts?

My guess goes with the mobo at least.

Two questions. What motherboard is it, and do you hear a single beep when the PC starts?

The effects of no/low power from the battery varies between motherboard. With many PC's, the PC will display the Checksum error, and boot normally with an incorrect time and/or date. With less fortunate motherboards, PC's can become unstable and very slow without the battery, something to do with the timing of certain tasks, but it's been a while since I was taught motherboard architecture.

If your PC beeps, then the processor is likely to be ok (a little concerned about overheating issues due to those two fans being faulty - overheating). We know at a minimum you'll need to replace those two fans. Some motherboards have an auxiliary battery connection you can use incase the main battery connector is broken or corroded. If you have one of these connections, you may want to try this before replacing the motherboard. If you receive a single beep, then you won't need to replace any other parts.

The motherboard from the OP
Im not sure theres even a PC speaker in there, cant remember and can't see one unless its tucked away. How can I "create" a beep to see if there is a pc speaker. I did not hear a beep just booting now, but unsure if there is a pc speaker lol.