If a person already has lots of computer games and still buys more is he sinning

If they get in the way of your time and fellowship with God they could be considered Idols. Just be careful not to put them before God. We all fall in to Idol worship of some sort sometime. To much T.V., To much attention to our car, House , etc. We have too many toys and other distractions on this earth and Satan will use them to his advantage. We have to try to put God first in our lives then he will bless us with much more than this world could ever offer. It is a fact that the more we focus on him the less importance worldly things possess. Matthew Ch. 6 verse 33.

No. It's not listed as Sin in the Bible. But maybe Yes, by excess..