Motherboard Asus A7V-E

I recently purchased a Asus A7V-E motherboard with a FSB of 200Mhz. I also got an AMD Athlon Thunderbird 1.2GHz 200 processor. I am also using PC-100 SDRAM. When I try to start it up after installation, the computer initially boots but then begins a constant beeping and flashing on the screen. I was wondering if anyone knew what may be causing this?