PC problem help

[Knave]

My PC has been running perfect without this problem ever but the past few days when doing (it can be doing anything) my PC just shuts down and starts up again with no warning or errors.

Only think I recently changed on my PC was I added a new PSU [Corsair CX750 Builder Series CX 750W] and added x2 DisplayPort to DVI Active Adapter for triple view.

PC is not overclocked and checked bios voltages and all seem in line with whats needed.
Just hard to try and pinpoint the problem with no warning or logs to help.

 

[Knave]

Temperatures are ok, almost the same as before the PSU change.
The old PSU was even a lower wattage of 650w and powered the system with no problems.

Whats also weird then it does come back on after going off all websites have forgot me and need to log in all of them (usually on a random crash or power off this never happens)

Temps at idle.

http://imgur.com/hZIgUZ7