不要把时间花在玩电脑游戏上。

Don't spend your time on computer games
或者Make your time clear from computer games.
翻译有很多种，第二句比较高级地道

Don't spend time in playing computer games.
语气强硬,,
不用please吧..

不要把时间花在玩电脑游戏上。
Do not spend their time playing computer games

Don't spend all your time on computer games.

Don't spend much time in playing computer games,please.

Do not spend their time playing computer games