New Computer doesnt work );!!

[Junes]

Hi guys (;
I've just bourght my self a new computer with the spec. listed below but i got a problem. after i finished putting it all together and started to install windows my monitor just sudently shuts off, every time i make it to the windows is installing fase my monitor just turns off ? but finally i got windows on it and installed all the drivers for the components and ofc counter strike source i then tried to run a video stress test in css, just to see how well it performes, but then in the middle of it my monitor just shuts off and says ''no signal'' and after a little after the computer reboots. and now it has problems just showing up the start page with the background and all that, with out it turns off the monitor, please help me !

Power: Ace Raw Deal 620watt
Motherboard: Asus M4N78 SE
Processor: AMD Phenom II x3 710
Graphics: XFX Ati HD4870
Ram: DDR2 Kingston 800mhz
Monitor: Acer V203W

Write if there is more you would know. PS: sorry for my bad english...

 

[konsole]

The computer doesnt just shut off the monitor. The monitor either goes into sleep mode because its not receiving any data from your graphics card, or you physically shut it off yourself. It sounds like your monitor is fine but it could be your graphics card, could be a loose connection between the monitor and graphics card. If your motherboard has onboard graphics try hooking the monitor into that and see if that fixes the problem. If it does then theres probably something wrong with your graphics card. The graphics card could be overheating, try the Catalyst Control Center for ATI cards and see what the temperature readings are.