I experienced some issues with my acer travelmate 5730 shutting down when I tried to install ubuntu 12.04... However I managed to install it and after a few updates the shutting down stopped...

But yesterday I wanted to plug in another monitor and set dual displays via AMD CCC. After setting dual displays I had to reboot the notebook. And since then the notebook has been shutting down soon after being turned on, not even letting linux or win to boot. I tried many many tricks, from updating drivers to reseting BIOS by pulling out the CMOS battery. I got to the state when I am able to boot linux by launching recovery mode, selecting the root terminal and typing restart... then the ubuntu boots and everything works fine. However, when I want to launch ubuntu normally, it shuts down while booting. I managed to look at the temperature a few times and it never got over 50°C... So I don't assume it to be overheating. I'm starting to think there could be a hardware problem... my graphic card is ati radeon hd 3470

Does anybody have an idea what might be the cause?