New Pc randomly reboots with no picture until hard reboot

[tekneek03]

Hey Guys I recently built a pc and in games sometimes it will just reboot and my monitor will stay on finding signal untill I hold the power button on the pc and hard restart it. Any idea what this could be?


The specs are
Antec 650w psu
Ripjaw 8gb ram
H61 motherboard, i3 processor
Radeon 6850 video card
Windows xp (for now)

 

[Outlander_04]

Not really enough information to diagnose the problem
and confusing

either it reboots , or it turns OFF
which. Describe in detail how it stops

 

[tekneek03]

Okay, I will be playing a game.. then suddenly the monitor will say cannot find signal, and ill continue to hear sounds on the computer for a couple more seconds then my pc reboots, During this reboot that the computer caused the monitor remains without a signal even though i replug it. In order for me to see picture again i hold down the pc power button until it turns off, then boot it up again and all is fine.