Asus Motherboard failed. Need replacement. Help!

Hey everyone. My Pc shuts off completely randomly. I've replaced and/or tested every single component except the motherboard. So now I want to order a replacement motherboard. I have an Asus P5ND2-SLI but would like to try out an Intel board or something else. I'm familiar with pc's but finding a motherboard that will work with my configuration is something I'm finding difficult. What are my options?

Here's my components:
P4 3.0GHZ 830 2MB L2 Cache DC Processor with Liquid Cooling
2- 1GB DDR2 PC4200 Memory Sticks
2- Nvidia Geforce 7800GT 256MB PCIE cards SLI
650 Watt ATX2.0 Power Supply with Active PFC Power Supply
Seagate Barracuda SATA 500 GB Hard drive
Soundblaster Audigy 2ZS
XP Pro

Here's a couple links to my current Asus motherboard -
http://gr.asus.com/products.aspx?l [...] odelmenu=1
http://www.newegg.com/product/prod [...] 6813131578

I also realize that my setup is getting dated and I might have to upgrade my processor or memory, etc.
Thanks for any help!
Tim

I replaced the power supply with another 650 watt. It had all the same connections, etc. The problem was unchanged. My current one is a Silverstone.