You're off topic for this forum, which is dedicated to Windows Live OneCare. You may want to try the Microsoft Public newsgroups here: http://www.microsoft.com/communities/newsgroups/list/en-us/default.aspx
It sounds like your modem - cable or DSL is rebooting or losing the connection, which means that you need to contact your ISP. Or, if you are using a wireless connection to your router, you have a weak signal or interference causing the network connection to drop.
-steve