OK, the 1st problem was a fan that did not work. A fail-safe mechanism

The computer wouldn't start because the fan did not work. I corrected that.
Now for a new problem... I managed to power u my PC, but shotly after being powered up it began to stink like hell. Like some bacelite was begining to fry.
Two questions:
a) could this smell come from the CPU? I applied a layer of thermalpaste - not too much though, but before that I removed the old one from the cooler with acetone [nail polish removal?].. could this one be now the source of the burning smell? ... however it seem unlikely to me since it started smelling/burning right after the power up..
b) Could it be that my power supply unit began to burn some materials inside?
Thanks in advance for the info !