Hello guys and girls, I bought a dell 4600 from a friend. It has been working just fine until last night. As I push the button on the tower nothing happens. A friend suggested I buy a power supply. So I bought a new power supply and still nothing happens when I push the power button. Someone else suggested cpu. The thing is I would take it somewhere to get checked out but I want to fix it myself. Can someone give me some tips on what to do?