I have just installed Windows 7 Professional onto my PC which was previously running Windows XP.
Install was a bit shaky with the graphics dropping out a couple of times throughout install.
After installation all drivers seemed to have installed fine, but I've run in to two issues. After a couple of minutes either:
1) The video feed stops and the monitor switches off. Computer doesn't respond and I force reset using the power button.
2) Internal speaker makes a constant buzz/beep sounds and all 6 Phase LEDs on the motherboard light up. Computer continues to work.
My research so far suggests it could be the graphics card or power supply. I've tried swapping for different RAM, and have also tried a different graphics card. The only possible cause I can come up with now is the power supply, but not sure how installing Windows 7 could have impacted power consumption.