Computer will not start

i just bought all the parts i needed to make my new computer. i am using an AMD athlon XP 2800+ processor, 512 MB DDR RAM, Asus A7N8X motherboard, and ATI Radeon 9700 Pro. when i had all the components hooked together, i started the computer and thebios loaded. next, i started to load windows xp on and it said it needed to format the hard drive. i let it format, then when it restarted, i turned it off. the next day i tried to turn it on, and the monitor did not receive a signal. the case and cpu fans still work, the hard drive is spinning, and the video card has power to it. i don’t know if the bios won’t load or what, but if anyone could help i really need it thanks