Go to his profile. VAC bans count over game engines, so if he got VAC banned in let's say COD, he'd be VAC banned from COD games, but not Source engine ones. Also, look at that screenshot I attached.
Wat. Boards have sockets, you know. You can't run an i5 4670k on an LGA2011 board, for example. Pls do research m8.
EDIT: Also, unless his processor is a Pentium 3 or something, he should probably get a GPU+PSU upgrade.