Plutonium

crash1999 as you can see it reads your username as "????" so the problem is most likely that your username contains special characters that the launcher can't read.

https://www.lifewire.com/change-user-folder-name-in-windows-10-5114140

Can you screenshot your MW3 folder? Also for clarification you did download it through steam right and not some trash nosteam/skidrow repack?