The 24pin should go into the 24pin slot. The only reason the 4pin part will break off is if you have an old motherboard with a 20 pin slot instead of a 24pin. Also yes the 4 pin is necessary, plug the 24pin into the 24 pin slot and then you should have an additional 4 pin connector coming off the power supply. That 4 pin connector is specifically for your processor and if im correct it might say P4 on it.
Dont seperate the 24pin and take the 4 pin you broke off and put it in the 4 pin CPU slot its not going to work.
Also make sure you power supply is switch on. There is a switch on the back of the power supply.
Also does the computer BEEP at all. When your computer boots you should hear 1 BEEP meaning that everything is installed correctly. If there is more then 1 beep then that means something is not installed or not installed correctly.
Edited by Lucky23, 02 May 2008 - 10:40 PM.