Most people will disable acpi, and maybe this will help you too, but i don't say that this is best solution or solution, let's try.
Sure... what ZEROF is saying is right.
If you are going to try this, keep in mind that now on you won't get any warning message from your OS on overheating, nor any action will be executed to prevent system damages. So, system health will be up to you. If you have a prolonged usage of your pc without a fan running, your temps will increase and you can even burn some hardware components.
It's like you are deciding to turn the air-bag off in your car, for the reason you don't want to repair it each time you have a crash. It's its function, the reason it was invented for... So the solution is not to turn your air-bag off, but stay away from dangers and avoid crashing... in the same way, in your case the problem is not the ACPI system, but the obstruction of the fan. Think about it, or you will run your system without an "air-bag".
It's strange you can't find that options in firefox preferences... you should have a thing like this:

Bye.
« Last Edit: March 31, 2013, 09:09:30 PM by b4d_bl0ck »
bool secure = check_paranoia() ? true : false;