Hai

In my office we have 100 systems.os is xp.people are playing online games in systems.I want to block games in systems.in Google they will play online games.I want to block all online games.with software are any commands.please help me out

Really depends on where these games are located.
If they are the online variety then you will either need to restrict access to the browser or the sites in general.
Either way you are going to have a massive issue attempting to stop people accessing this type of content.

Some corporate internet filters do a good job, but there's always ways round these.