Why does my netgear router keep disconnecting ?

Almost every hour I have to unplug the router and boot it up again, because the Internet just shuts off. It says connected on my computer but says no interent accesses. I have a netgear 54mbps wireless router WGR614 , how do I prevent from doing this almost every hour. It works fine whenever I reboot it but it's just annoying to always have to do!!! & do I need to upgrade the firmware & if I do what will that do.