rosalie, If blender under warranty return for replacement,repair/refund. It sounds like the bullet has an internal switch issue. Below I will post a link to show how to dissemble the blender so you can clean/check/replace switch if need be. If not wanting to work on the blender yourself take into a good local small electronics repair shop and have them take a look and estimate repair. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.

Magic Bullet Teardown