Alienware x51 won't respond after Microsoft update

On Sept 30th, 2016. I usually keep my computer on and when I'm not using it, it goes into sleep mode about 5 min after I stop doing anything on it.   I was working on a document, then I had to leave my workstation for 3 hours and when I got back, my computer had been updated by Microsoft because when I awakened it, it said updating...30 percent...then it went to the sign on screen.  I entered my pw and the start screen comes up but it seems t0 be extra slow .  I tried to go online and I can't connect.  I tried to turn on the calculator and it wouldn't do anything.   I tried to turn on several programs but none of them would start.  I can do limited things and when the limited items ask me to keep going...yes or no...if I hit yes, all the icons, everything on the start screen disappears aND the screen goes very dim...if I hit escape, the screen goes blank.    I ran an ePSA test by entering F12 and it says one or more thermal sensors are out of range.  Error code 2000 o314 and the computer is playing a tune with beeping noises.   Can someone tell me what needs to be replaced or what is wrong ?