Thank you all! Excellent posts all round and not one of you called me a fool for falling for a potential scam.
The machine in question is my mining rig and as such I don't have any real information on it and it is still mining to my wallet.
To play it safe I am going to follow your advice and do a fresh windows install and flash the BIOS.
Probably a daft question but is it remotely possible that TeamViewer could have transmitted the virus to my other computer?