Clean our personal computer with vacum cleaner

It is a week already that our computer is very noisy and slow. I asked my son what is the problem and he said that our personal computer's motherboard is full of dust and needs electric blower to clean. He want me to buy one. I said to him that he must be resourceful. We have already a vacum cleaner to use. There is no difference with the blower and i think vacum is even better because it will suck off the dust not like the blower. It blows the dust all over and we need a double face mask to protect us from inhaling the dust. My kids only know how to use the computer excessively but didn't care to clean. He is waiting for me to buy electric blower. But i insisted to use the vacum and he did. Now, our computer performing fast and no more noise.