Laptop (windows) suddenly crashes?

I have had the following problem for some time: When I play / work with my laptop, I have connected my laptop to the power cord, even if it is already fully charged. Sometimes, however, my battery level changes from 100% to 0%. When I switch my laptop back on, it is full again, and I have no viruses or anything. Need advice.

Take the battery out when you use it on the power. And buy yourself new ones.

The battery is broken, save the data on an external hard drive for as long as possible and send the laptop for repair or get a new one