|"it specifically says that it needs PC2100 RAM. I edited out my comment. Sorry about that, I just thought that motherboards with a system bus of 400MHz needs memory that runs at the same speed"|
Don't confuse FSB with frequency. The CPU runs at 100MHz, PC2100 runs at 133MHz (266MHz DDR). That puts the ratio at 3:4, which is exactly what you want for a 400MHz FSB P4.
"would the voltage problemmost likely be whats causeing the crashing?"
It's a possibility but not a sure thing. Did you check the BIOS to see if there's a RAM voltage setting? Before buying more RAM, test what you have using memtest86. You should ALWAYS do that anyway. Test each stick individually..if they check out OK, test then together. If you encounter errors (& there's no voltage adjustment), see if you can lower the RAM speed to 200MHz DDR, then test again.