I have a Dell Inspiron 14 2530 with Ubuntu 12.04. Once in a while the system freezes completely (can't move mouse, keyboard won't work, no HD led blinking) for no apparent reason. Sometimes I haven't even started any programs.
Anybody got the same issue, or knows what could cause such freezes? Currently I'm dealing with it by hard rebooting the system, and hoping it won't happen again.