ubuntu suddenly started freezing during boot up

view story

http://ubuntuforums.org – for no apparent reason ubuntu (12.04) suddenly does not boot anymore without displaying an error msg. sometimes it shows the logo, sometimes not, so it's not the same place where it freezes. btw booting from an ubuntu (13.04) stick also freezes the system. i have a dual boot with windows 7 which incredibly enough also freezes during boot now. safe mode works, but start up recovery freezes as well. maybe a hardware issue? thank you for any leads on how to pinpoint and solve the problem. (Hardware)