LAN devilry

I've got two boxes, both running XP home, networked via a netgear pr614 router (cat5 from each computer to the router). Cable modem is plugged into the router.
Every couple of days, one of the computers loses its connection. No email, web, can't ping google, ipconfig does nothing (because there's no connection!).
Quick fix: reset the router. After it's been unplugged for about 60 seconds everything is cool again, connection is restored.
I was wondering if anyone else has encountered this, and if they had found a slightly longer-term solution....

Does the router have the latest firmware? Is it always the same pc that loses the connection?

It is always the same computer. The firmware hasn't been updated in about a year, so that is something worth looking into again. Hadn't thought of that. Thanks.

Try changing your cable to see if that's the problem.

Changing cable as in replacing the cat5? Or changing the cable as in using different ports on the router?
I've already tried using different router interfaces (there's only four, so it wasn't a very extended trial).
If updating the firmware doesn't have the desired effect, I'll try replacing the cat5. It'll be three or four days before I know if updating the firmware worked.

Changing cable as in replacing the cat5, make a new cat5 complete, I think changing ports on the router is not the solution. Have you try to use one of the "offending port" on the other pc once it is not working?

is the connection loss a set period of time, like every 3 days, or is it 3 days sometimes and 4 days other times, etc?

If it's always the same amount of time, then it might be dhcp not renewing the IP address, if the lease time is the time it takes to lose the connection.