Computer goes into power saving mode when playing games

Hi.

I hope someone can help.

Recently my computer started going into power saving mode when playing games on my computer. This happened about 15 minutes after loading the games. It seems to happen when I use my gaming controller (a Saitek P2600 rumble controller) to play the games, although I have been using this for over a year now and have only just started getting problems with it.

I have adjusted the monitor power settings in properties, changing them to never turn off monitor, but it still continues to go into power saving mode when I play games.

It has happened to more than one game, so I know it is not the games themselves.

Hopefully, someone can help me resolve this problem as it is driving me crazy having to restart my computer every time!

Many thanks.

Kirsty.