I'm trying to install ubuntu-12.04-desktop-amd64 from my usb stick. When booting from usb I instantly get a blank screen (with a grey box at the left bottom) I checked the live system with my laptop.works well except it also starts of with a black screen and a grey box at the bottom. I figure the Problem is my geforce gtx 570 since older versions of Ubuntu where only able to boot with xforcevesa and nomodeset. Unfortunately I can't change the boot parameters. I tried the alternate version for a text based install, but it has the same problem. If I press Esc in the alternate I get a message box with two buttons but no text. I would be happy for any advice on this matter