I have a HP G62 with i5 processor, 4G Ram and ATI HD 5470. Started using Ubuntu 4 months ago, first was 11.10 and after 12.04. Everything worked perfectly until some weeks ago when my cpu fan became "crazy" and I mean by this always on, noise and overheating problems, for sure if I put a glass with water in some minutes will boil (and I mean it). There can be a bug in the last kernel or any other Ubuntu's official update?
And by the way
CPU fan is cleaned like a new born baby;
Used jupiter and all those stuff (lm-sensor, psensor...) - same problem;
Installing ATI drivers don't work very well. (interface laggy as HD 5470 isn't supported by Ubuntu) and I can't even open ATI Catalyst (error when I try to open it), more than this I always used open source drivers and as I said, worked perfectly (3d, effects).
Right now I'm back to Windows and everything is working perfectly but my main problem is that I get used with Ubuntu and kinda weird to use windows again. I want back my nice and almost perfect Ubuntu.