Controlling the fan manually?

Can you turn on the fan on a laptop or let it run at maximum without getting into the os or bios?

Disassemble and connect to power source

Yes Are there three cables you just have to hold the black and the red to a battery?

Try the MSI afterburner.

https://de.msi.com/page/afterburner

The problem is that I can't get into the BIOS or Windows…

Yes, I'll have a look. Is a middle class laptop that unfortunately got some coke so that the fans no longer work

OK. Make sure you remember how they are in the laptop at the end, i.e. The order of the cables.

Yes

May not harm