|this is exactly what i have got on hp 6720s. also, monitor connected to laptop will behave normally. also, you may notice that when you booting, the black part on right side is already ignored blank ie. no text shows there, it is like shrunk.|
I have FIXED this problem by flashing BIOS. You need to search a tiny bit to find manufacturer's BIOS for your laptop model.. ..be careful about what you do, although it is really fairly simple.
good luck and have fun, have some sex with your husband