Hi again,
Regarding upgrading the BIOS etc, did you try resetting the BIOS to defaults using the jumper after upgrading, sometimes an upgraded BIOS can be confused by old settings and fail...
And maybe a more robust OS such as WinServer 2012 setup for a "Desktop Experience" may help with so many processors, processes and threads. You could try the Trial edition but don't forget to get the genuine Nvidia drivers, I believe the MS ones are crippled/limited.
Hope this helps,
Scott K