home network problem

i have set up a home network for me and my rootmates so we only have one cable modem to pay for. the router is a smc7004vb2 set to factory defaults and the most updated drivers. one system is usinf xp pro the other 2 have 98se. the problem is losing the connection and the only way to get is back is to reboot the router. all three systems don't lose the connection at the same time,one will lose and the other two can still get online. when these first happened xp was giving me dhcp errors so i turned off dhcp and gave each system a static ip, and the problem still exists. the xp system lost the connection today and there was no errors or warnings in the event viewer for today. the fire wall that comes with the router has never been on and i turned off the firewall that comes with xp. i don't know what to ckeck next. as far as i know everything is configured rigth and i did check to see that my system had the most current drivers. is there something i can run in the background that i can use to pinpoint the problem

i don't know what to make of this. i lost my connection, so i gave my system a new ip and i got rigth back on. have no idea why i lost my connention in the first place. xp didn't record any errors or warnings