CymTyr: Knee, turning your modem on and off won't work.
What you have is a dying modem. To get it to behave until you get a modem replacement, you have to power cycle. You need to shut your pc completely off, and completely unplug the power from the modem for 2 minutes.
Power the modem back on, wait for all the lights to fire up, and then when it's completely on, turn your pc back on.
This is a make-shift fix until the modem gets replaced.
That is a good theory, but..
I have another modem, brand new. It doesn't work either.