Never fooled with a P4 before

[Sniper82]

Is it just like putting together any other system other than the PSU connectors? Is there 2 that needs to be connected or just the 1 4 pin connector?

 

[mechBgon]

The 20-pin and 4-in-a-square for sure, and if it's got a third fitting for a hard-drive plug, that wouldn't hurt either.

 

[Duvie]

some of the early p4 ddr mobos by asus had the "ezplug" or 4 pin molex connector as well for those with older power supplies...some say that helps by having them both plugged in...

 

[AndyHui]

This should help:

AnandTech FAQ: Do I need to plug in the ATX12V connector on my Pentium 4 motherboard?