Can my computer catch on fire from dust?

-I have this 3 year old stationary computer of mine that i have never looked inside of. Who knows how much dust has gathered there by now...Dust insulates the machine, making it store heat easier.

It can also slow down your fan, slowing ventilation.



Dust will increase the chance that your computer will catch on fire, but the chances are still very, very low.
The chances of your computer are almost zero. What you should be worried about is the fact that when your system gets dusty like that, your computer can slow down considerably. It happened to me in the past.
The odds of it catching on fire is insanely low, but it is possible. You do not need a spark to make a fire if there is enough heat.
Sure it's possible. It would need a component in the computer to emit a spark.
No. Unless you put a flame super close to it or something dumb like that...