I have had an Asus G73J series for a bit over a year now. Recently after turning it on, it will boot all the way to my desktop, after that all programs take a lot longer than usual to load up, the sidebar processor meter will stop displaying any processor activity after a few seconds and after a few minutes my computer will shutdown. A burning smell will usually come out of the heat vents at this point.
I have had my computer overheat in the past while playing some demanding games, but unlike when it overheats, after these shutdowns i can power it back on immidiately. Also overheat shutdowns have never produced any burning smell.
These shutdowns will also happen in safe mode. I had read that a faulty PSU could cause computer to have similar issues so i tried another one and while it lasted a bit longer than usual, it still did shut down.
Also got some error about asus controldeck, im not sure if this could be the cause or just a sympton of a bigger cause.
I can hear the fan working, i checked the vents to be unclogged by dust and i feel air coming out of the vents so im assuming it is not a faulty fan issue.
Still sounds like overheating. How did you checked the wents?
Sometimes a surprising amount of dust can accumulate on the other side of the radiator, maybe it doesn't look like it from the outside.
Have you tried to blow air (possibly compressed air) into the vents? With the backside service panel taken off? Maybe some blown dust particles travelled near the hotter parts, and are burning there, thus the smell.