monitor issue

[Jimmy Bradley]

I"m running Ubuntu 12.10.
I've hooked the pc up to our 42 inch samsung plasma tv, via the pc
monitor connection on the back of the tv. I have a ton of movies and tv
shows stored on the machine.
The problem I'm having, and haven't been able to solve is, if I don't at
least move the mouse about every 5 to 10 minutes, the tv screen goes
blank, even when I'm playing a video file. It's acting like it would if
the machine was sitting idle.
I've gone into the power management settings and have all the power save
settings set to " never" or "don't suspend" and it hasn't made any
difference. I've tried hooking the machine up to a pc monitor, and it
does the same thing.
Does anyone by chance know how to solve this problem?

Thanks

Jim