I don't know how to go into bios but after rebooting it's now reading 22-23cº
That's a bit more reasonable. 22 C is about 72 F, decent room temperature. Is that after the computer sits idle for a few minutes?
To get into BIOS, you will need to press a key before the Windows startup screen appears. It tends to be different across motherboard manufacturers, but usually either F2, F10, or the DEL key.