Yes.So i bought this PC off a friend for 150 pounds which is amazing. He has a poo processor though. I want to upgrade but have no clue what motherboard his PC has. I asked him, hes forgot. Will i have to open the PC to find the model number?
Yes.
Take the side panel off. There should be info printed on the motherboard.
As above, CPUz. Also, Speccy.
You need to determine ALL the parts in it.
Also, plan fo a full wipe and reinstall. OS and everything else.