Motorola sbg900 wireless modem (by 3 users)

have you tried powercycling your modem?
turn of your computer, unplug the power cord from the back of the modem. wait a minute (literaly).
plug power back into modem and wait for lights to come on and stop flashing. power computer back up.
Check to see if connections works.
Also check your cable connections between the modem and the computer.
If all fails contact your Internet Service Provider, who most likely provided you with the modem.