Windows 7 keeps sending monitor to sleep

Hi have had this problem since I can remember, after about 20 minutes windows will send the monitor to sleep if its idle, The picture will fade away and then the monitor says no signal is being received, its the same on both my monitor and TV . I have changed the power settings to Never on both "Turn off display" and "Put the computer to sleep".
I'm really not sure when this started but it makes it impossible to watch films or play games when using a controller. I also have no screen savers set.

specs if it helps:
Asus M4A79XTD EVO Motherboard
AMD Phenom II X4 955 Processor 3.20 GHz
2GB RAM
NVIDIA 9600GT

This is probably something simple but I'm really not sure what to do. I searched a few forums and found a few similar problems but no solutions have helped me yet.

Hi thanks for the quick reply, set hard disk to never, played a game for 20 minutes using a controller and the exact same thing happened. Do you have any other suggestions? Thanks for the help.

Nope no change. Its still switching off after 20 minutes.

Rightclick on desktop, select Personalize, set screensaver to None.

Check your monitor's manual for any sleep settings: go to maker's Support Downloads webpage for the exact model, read Manual. Check optional Updates for newer monitor driver or other newer drivers.

If it is not Power Options>Display, or ScreenSaver, then it must be monitor itself.

Did you try the Ctrl-Alt-Del thingy to see if the monitor wakes up?

Also

If you are using W7

Go to Start
Type Screen Saver
Click on "Change Power Savings"
Click "Change When The Computer Sleeps"
Make sure that "Put The Computer To Sleep" says Never
Click on "Change Advanced Power Settings"
Click on "Sleep"
Click on each of the four options and see what they say