Recommended

Rust, CS:GO.

Damn thats almost exactly my computer 3-4 years ago, go for css, csgo. You probably can't run COD very well. Get an upgrade get like 4gb's of ram and and a new graphics card.

would recommend dayz but I think it would be choppy on that computer so ill recommend rust.

CS:GO and CS:GO. Also, CS:GO

League of legends

The ram def needs to be upgraded. Id say 6. Then you could run world of warcraft and everquest and some other semi big world games on low settings.

Switch to 64 bit OS..

I believe he will have problems running Rust considering Rust is still in alpha and is not fully optimized yet.