1 Answer

Usually, routers will have a 'redial period' that will automatically re-connect a dropped signal.
Most routers will also have a 'time-out period' that will force everyone off the internet. This is easily adjusted via the router's configuration page.
If you change the 'time-out period' to a longer length of time, that will delay any inconveniences or dropped connections, but not forever.
When mine times out, I just unplug the router for a few seconds, and then plug it back in (power, not ethernet).
You don't have to restart all your computers. If you encounter any problems after reseting the router, try disconnecting & re-connecting to the network.
Consult your owner's manual for more details on configuring your router & modem.
PS: Check that your hardware and software settings are correct. It might be a stupid mistake like:
> Using both dynamic and static IPs on one router --This will block computers from accessing the network. Make everything static, or everything dynamic.
> Trying to share a DSL line incorrectly --If you are using DSL, be sure to use PPOE as a connection type. Provide your router with a username and password.
> Using the browsing software that came with your modem --DSL providers often include browsing software with their modem, but only allows one user at a time. Use a common browser such as IE or Firefox. If ANYONE is using the included software, everyone will experience problems!!!

Source :http://answers.yahoo.com/question/index?qid=20070504104338AAv2qXE