Hello, I have a i7 based HP computer here that until recently was booting Linux and Windows just fine. According to the user, it stopped working after updating the graphics drivers under Windows. Anyway the symptoms are: * Grub loads fine. * Selecting any Linux kernel from grub, results in the computer freezing immediately after loading the kernel (no time to initialize the kernel), with a black screen. * Selecting memtest results in similar problems. * Same thing happens booting from rescue items in grub menu. No extra debugging information. * Keyboard unresponsive after crash. Caps-lock, num-lock, and Ctrl-Alt-Delete don't work. * Booting windows works fine. * Booting Debian live CD image on USB works fine. It has the standard Debian wheezy kernel, 3.2.0-4-amd64, which is the same as one of the options I was attempting to boot from the hard disk. * Power cycling is the only way to un-crash the system. Extra facts: * It is a Nvidia GeForce GT 640 based graphics card * The live CD does not use grub. * Debian/wheezy based system with extra kernels installed from Debian backports. * The dog barking does not make any difference what so ever. * Nvidia closed source drivers not installed (not that I see this making any difference, as the kernel doesn't appear to be started when it crashes) * This is a UEFI boot system, with secure boot turned off. Have tried installing another kernel after booting live CD, and reinstalling grub, however nothing changed. Have run memtest from live CD, no errors reported. Only thing I can think of is that the update of the graphics drivers under Windows has updated the graphics card firmware breaking boots from the version of Grub in Debian stable/wheezy. Does this even make sense? Any other ideas? Thanks -- Brian May <brian@microcomaustralia.com.au>