Roomba discovery. My roomba comes off the charger and will go about a minute and a half. Then it

Question

My roomba comes off the charger and will go about a minute and a half. Then it will stop and beep once. i checked roombas sight and they said that the brushed need to be cleaned. I cleaned the brushes 6 times. It still does the same thing. I bought it from you in November of 2007. Should I bring it back to your service department?