Recently, I got my parent's old broken HP Pavilion 6355 that they had bought in 1998. Basically they said that if I could fix it I could keep it. I opened the thing up to see if there were any broken wires, connections, etc. inside the tower, and lo-and-behold there were huge clods of dust. I'm talking shag carpeting here, people. I did a little research online and found out that dust is the #1 cause of computers breaking (Not to mention T.V.s, video game consoles, and lots of other stuff).
So, basically, in this 'Ible you will learn how to properly clean out a computer tower.