I built a brand new system from all new parts last May and this June the PSU straight up died. It would just not power on. The PSU was still under warranty so I mailed it back and it was promptly replaced. I installed the new unit and the machine booted as normal except for when it got to the windows 7 loading screen after a few seconds of the loading bar the power will just cut out and the machine will then sit powered down for a second then power back on. I have tested everything and found no errors. I even removed unnecessary hardware and attempted to boot to Ubuntu from a USB drive but the same thing would happen. However with Ubuntu it would reset at different parts of the loading process. I tried booting to the windows 7 CD and it would reset at the loading screen as usual but when I unplugged all hard drives it would get to the windows setup screen. I even tried to do a fresh install on a new hard drive but it still resets. The strangest thing is that I can boot into windows 7 safe mode with networking, browse the internet and such.
Any ideas? I am stumped. I have built several PCs in the past, have a comp sci degree and have never ran into something like this. I am about to pack up the PSU again and mail it back for another replacement but before I do does anyone have any suggestions?
Do you have a multimeter to test your psu/cable connectors?
Since you say everything seems to work ok in Windows 7 safe mode...
nvidia graphics card driver? In safe mode, use device manager, to change it from the nvidia driver to the generic vga adapter driver, restart into normal windows, and do a clean install of the latest whql nvidia driver.
As far as the ubuntu issues, it might be a separate issue considering your experience with win7 safe mode.
I fear that the motherboard has been damaged. I have been talking with gigabyte trying to determine that but they are not so helpful. I have the resetting issue using the USB drive to boot Ubuntu so doesn't that kinda rule out the sata controller? I changed the drives to IDE and got the same results.