Few days before, I have upgraded my OS from 12.04 to ubuntu 12.10 (quantal) 64-bit. Ever since that, when I try to boot my notebook with any cable connected to it, the screen just remains black and nothing happens and I have to reboot my notebook by force(holding power button). With no cable connected, ubuntu loads just fine and than I can connect everything and there is no problem.
I guess, that it freezes before the kernel is loaded, because when I tried to reboot the computer using alt + screen + b, nothing happened.I was experiencing these difficulties even on the previous version, but just sometimes. I am running DELL Vostro 3750, and having also installed windows 7 next to ubuntu.
Please, does anyone have any idea, what may be causing this?
Edit: Maybe I should have also included note, that it freezes after I choose in grub boot menu, what should be booted. But not promptly after I select it. For about 5 seconds computer seems to be doing something (disk control is blinking).