When the cpu gets too hot it'll throttle itself down to prevent overheating. If the airflow is blocked, it'll heat up pretty fast and probably shut it self off from hitting its safety temp.
thx but out of curiosity what could happen if the airflow is blocked? would it cause it to slow down?
Yes, as already answered it will slow your pc down, massively if its too clogged and your pc will just shutdown all the time to protect itself, look on youtube for cleaning dusty pc video's, theres some really grim ones hehe,
and Thank you for B.a., glad to help
Moto