Hi, I get a strange result when using glutFullScreen, just imagine :
First , I run my program. Runs well.
Then, I close it and wait 15 minutes.
The monitor begins “sleeping”.
Then , I wake it.
And there is the problem : The display crashes !
And this does not happen if I don’t use glutFullScreen, or if I let only the screensaver but not the sleep.

Do you have any Idea ?

I guess that glutFullScreen is not guilty even if it looks so. After all does it just expand a window.
I would instead look at the power management for the monitor. Try to disable it in BIOS and check again.