When I turn it on it doesn't start out in the circle motion but starts and than stops and than starts and than stops and moves erratically and than totally stops.

Are you getting any error codes? Could be a bad LED sensor on the front bumper. Or a stuck wheel? Take a look at this - https://homesupport.irobot.com/app/answers/detail/a_id/7265/~/the-roomba-800-series-error-messages-chart.

Usually this means that you've got a resistance or a lint clogg at one of those to drive Wheels this is what causes it to Circle you have to dismantle it and clean out all the lint and hair or anything else is trapped in those Wheels

Check all the wheels to make sure that they are ok. Check the sensors on the bottom and make sure they are all clean.

That is probably the belt. Open up the bottom screws and take a look. The cat or dog hair usually gets stuck in the ends of the rollers and stops the belt from effectively pushing the roller. You may find that the belt is still on the drive and the roller. If you do just clean out the roller.

Your bump sensors are malfunctioning... The best thing to do is order a repair kit. I ordered mine from EESolutions.ca and it worked great. I'd recommend them.

CHECK CLOSELY WHAT STOPPING IT MOVE

i just recently had someone bring in a roomba discovery and all it would do is stay in a tight 4 tile area and go in circles. battery was fully charged and all bumpers were clear.

i took a can of air blast for cleaning computers and blasted the area on the bottom underneath the sensor and watched as several dust bunnies came flying out.gave it a few more blasts for good measure and put it back on the floor and hit power then clean buttons.

thing went in same tight circle for 2 passes then the circle got bigger for 2 more passes , blue light indicator came on and it made a straight line dash across to closed door and started following the edge and criss-crossing the room.

called the owner back in to test and it repeated the same moves when she started it and all appeared to be working normal again.

Mine did a similar thing. I kept trying to use it anyway, when it made a violent jerk (I thought it had broken something) and it started to work again.

Have you tried pressing both buttons at the same time to make it go straight ahead? It might work.

I had the same kind of problem with my model 400 today...after starting it and having it go in a circle for 30 seconds or so it would finally run into something and then back up a few inches, turn, then go forward a few inches, then back up a few inches, turn, then go forward a few inches, etc., etc.. I tried cleaning off the four pairs of sensors under the bumper and blowing out various things underneath (by mouth since I didn't have any canned compressed air). It didn't really help. It then occurred to me that I had a leaf blower! I put the Roomba upside down on the grass, put the leaf blower on high, and blew at it from all directions and up close. More dust came out than I thought would. It has been running normally now for the last 45 minutes.