because it's not a Pentium 4 motherboard
the Pentium 4 motherboard is exactly the same in terms of what power supply you can use except for the extra 4 pin connector. even if your motherboard doesn't use it, you can still use a PSU that has that connector
as for RAM, I would get Kingmax, it is good quality, cheap and runs on lower volts than other RAM
for a video card, if you're doing light gaming, I would recommend at least a Geforce FX5200. if you want to go higher end go for a Radeon 9600 Pro or XT, or even higher, a Radeon 9800 Pro, or even higher still the Geforce 6600 (AGP not PCI-E)