When it disconects how long does it go down for?
The lights may be different on your
modem, but generaly you will have three lights, A solid
Status light means you are conneted to the cable company, A blinking
Link light means your router or computer is connected to the modem, and an
Activity light that will light up whenever you send or receive data to/from the Internet. If the Status light goes off when you loose your connection then it is usually the cable company's problem (unless your modem is going bad, not as common though).
BroadBandReports.com (formaly dslreports.com) is a great site for advice, reports, and tools. You may also want to download
Ping Plotter .
Install Ping Plotter and play around with it a little just to get familar with it. If your connection goes down again, and your status light is on solid on your modem, then run Ping Plotter and see if it connects to anything. If you are connected to your router, the first hop (ip address) at the top of the list will be your router, the second hop will be your modem, and the third hop will be your cable company.