my fan dosnt work, the one inside of my power supply. but i here the power running. but ever since then i cant boot up my computer..at all! plz help me!!

Simple, replace the power supply.  It sounds like the power supply has gone bad. Also make sure that the power supply you get has high enough wattage for your computer. An underpowered power supply will eventually burn itself out. Don't try to fix it youself. Those puppies can still hold power after you turn them off. Just replace it and hope that the mother board isn't fried.

The problem will probably come with your power surply, since you added a new fan you will probably have to buy at 350 or 400 watt power surply, doing this will make sure you have enough power for all your extras!