Decent computer to run GMOD & CSGO

[Gobdonuts]

I am currently looking for a decent computer that will be able to run garry's mod and CS:GO at a solid 30fps. My budget is around 300$. Thank you for you're time. Also, is it possible to change the processor & graphics card in a all-in-one 18" ?

 

[netnavi01]

thats better already ! although if you are still unsatisfied overclock it