Just updating thread - it was 100% the PSU. I put the 875 psu in and booted up let it run for 45 mins no issue then ran Full Diagnostic test from dell and loaded a few games.   Thanks for responding 
Hello, Alienware Desktop R3 just randomly started to shut down last night, so after cleaning it out really good I really thought that would of worked without bad it was dust wise but no luck. It basically shuts down after 5-10 mins of running just idling on desktop. I was watching the thermal info and it never got above 73F if it hit 73 it was at it for maybe 15-20 seconds before going down to 71F then it would power off.  is this really over heating? if so just go ahead and replace all Fans and psu? This is a really basic install of windows 10, Chrome & Office 365 and TrendMicro are installed that's it besides Stream  SSD 500GB  9GB memory 320-2095 : AMD Radeon HD 6950
Aurora R3, shutting down