EliseDoyle, Make sure you install new good quality batteries and battery contacts are clean, then try Mip on smooth surface. Below is some trouble shooting steps from ifixit WowWee MiP Robot trouble shooting 2nd link below. Other links can possibly get you access to the robot inside to check/clean/reseat connections/components for damage/loose. Could not find much for replacement parts like new Accelerometer or Gyroscope Sensors, may have to search Ebay, etc.(4th link) and find a used robot for parts. If just not interested in trying repair or still under warranty use the last link below to contact wowwee to see if they can help or a good local small electronics shop if out of warranty.
MiP Keeps Falling Over, will not balance or stand upright.
-MiP is Not Powered On, Turn on the MiP using the power switch on the back.
The MiP may have a temporary software error. Try restarting the MiP using the power switch on the back. Switch it off for 20 seconds, then power it on.
-Low Battery,Low battery power may cause a slowdown or loss of functionality of the MiP. Replace the batteries.
-The Wheels are Stuck or Damaged, Dust and dirt may gather in the wheels or axels of the MiP. Follow this guide to remove the MiP's wheels and clean them.
-The Accelerometer or Gyroscope Sensors May Be Malfunctioning, The sensors may be malfunctioning and need replacing.
-The Motors may be Damaged or Malfunctioning, If the wheels are clear of obstructions or damage, the motors may be malfunctioning. If one or more motors is moving too slow or not at all, the wheels have excessive resistance to movement, too little resistance, or make strange noises the motor may be malfunctioning.
WowWee MiP Robot Troubleshooting
WowWee MiP Robot Repair