This could be in your monitor, screensaver, or other power settings. I can't tell you which but the pattern you describe makes it seem like a strong possibility. It could even be a port setting as some can be set to turn off to save power when inactive for a specific period.
Using HP 8000 Elite unit. When watching Netflix everything fine for about 2 hrs. then screen goes black and says no signal and will do this every 15 mins. thereafter. If I bump mouse pic comes back. Had this problem on older comp. some time ago and someone here told me to change a setting. I don't remember what or how tho, can someone please help.

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