Without the model number of your Eureka Boss bagless vacuum cleaner, it is difficult to access technical information and troubleshooting to help you with this problem. Here are some general tips that may help:
Unplug the vacuum and check the roller to see if it will turn by hand. If it is bound up with hair or fibers, you may need to pull the roller off and clean it. Follow the instructions in your owner's manual for this task.
Check your settings. Some Boss vacuums have a switch that will turn the rollers off for the bare floor setting.
If your roller is driven by a belt, check the belt to see if it is broken.
For more specific help with your Eureka vacuum cleaner, resubmit your question with additional details and the full model number of the unit.