need help

hi i have alienware m17x r4 and it get freeze with black screen when i play  any game or sometime using browser but when i  use  my  laptop  with  battery  i am  able to  play games  without  any  error . i have  run ePsa test (f12) and  it  said  no  problems  detected also i have run dell online complete diagnostic test while on battery (on  ac adapter my pc gets freeze)it gives  blue screen warning , i hv  done as  troubleshooting said and i have latest nvdia gpu software and bios  , Also i first thought it  would be  adapter problem so i ordered new  adapter but  problem still continues . Pls help