help pleaseeee?

[afaque]

hello friends..

i inserted a new ram stick of my friends. in my pc which i got from him today as i was playing dead rising 3 on 4gb of ram which caused the game to stutter a bit but after i installed ram stick.. i started my pc and it just worked fine.. after that i started dead rising 3 and got to my game but just after the loading screen.. my pc hanged on black screen death.. and i force restarted it.. then it just kept on restarting with no display.. i unplugged my gpu.. unplugged my fan connectors.. but then again no display.. then i unplugged my hard disk and cd rom sata cables from my motherboard.. and it started working.. and now plugged everything back in.. and its working fine.. please help..i wanna noe what is this problem and wanna noe how to diagnose it.. is this a psu problem? or some other??

[Clyne]

lack of ram? system requirements says need 6gb of ram 

http://store.steampowered.com/app/265550/

[afaque]

i installed 6gb of ram

2gb of stick i installed extra after which my pc shut down if you dont understand..i had 4gb before.. but when i installed 2 gb which was my friend's more.. my pc shut down and started doing this all.. can you help plzz

 

lack of ram? system requirements says need 6gb of ram 

http://store.steampowered.com/app/265550/