I've installed ubuntu 12.04 (the 64 bit version) and it crashes when opening a program. Sometimes this is with starting a virtual machine with virtualbox, sometimes with any other program. It doesn't always crash, but it does crash too often (daily). It has this problem since the first time I ran ubuntu on this machine and i didn't change any settings.
With crash I really mean crash; there are vertical stripes all over the screen and you can't change the num/caps lock lights on the keyboard, let alone go to another tty with alt+ctrl+f#, so i just have to turn off the power and reboot. The machine doesnt have this problem when booting windows 7 (not virtual machine but from grub). I haven't tried another linux version on this machine yet. Machine has an i5 4x3,33 Ghz cpu and 4Gb ram.
How can I solve this problem?