Starting this morning, while playing Final Fantasy XI, my monitor went black and said 'power saving mode' while the game music continued to play. A moment later, the computer shut off completely. I rebooted and started the game again, ~10 minutes later, it shut down again and I started to suspect this was a more serious issue.
I turned the computer back on and did NOT turn on the game, however the computer continued with this behavior. I assumed this was an overheating issue so I searched around with the laptop and found a program called everest, turned the computer back on, downloaded it and ran it quickly before my computer turned off again. I looked around for a temperate gauge for my computer but it doesn't appear to be running high. However I could be wrong.
This is my computer.
The only difference being I replaced the video card with Nvidia 9800 GT several weeks ago. I thought this might be a power supply issue also, however I have a 480w Power Supply and the graphics card recommendeds a 400w Power Supply, however I am not sure what else contribute to the power supply factor.
Any help and hints would be great, I feel like my day off is wasting away...