Hardware issue

[victorgrant]

Hello,

Since last week I'm the happy and sad owner of a new Nvidia GTX 480 card,....and Octane Render
First I had a hardware issue with my PC when I started up Octane my PC just turned off.
....the Power supply was not strong enough .....550W...
Now I bought a 850W and that issue was solved....I was happy again.
But now a other issue....when I start the render.. my Displays goes black after a minute or directly..... GTX 480 seems to turn off
but the PC is still running.
I have reinstalled the latest Nvidia driver... but still the same.
Now my question......
-Did someone of you had a issue like this and can you tell me how you fixed it?
-can it be that my PC / Hardware has not the right configuration...it not a new PC.
I could not find the Hardware requirement for the GTX 480.

Any help will be apprecited.

I didn't find the right solution from the Internet.

References:
render.otoy.com/forum/viewtopic.php?f=9&t=2086
Animated Device Explainer Video

Thank you.