error: mysql shutdown unexpectedly.
1_ Rename the folder mysql/data to mysql/data_old (you can use any name)
2_ Create a new folder mysql/data
3_ Copy the content that resides in mysql/backup to the new mysql/data folder
4_ Copy all your database folders that are in mysql/data_old to mysql/data (skipping the mysql, performance_schema, and phpmyadmin folders from data_old)
5_ Finally copy the ibdata1 file from mysql/data_old and replace it inside mysql/data folder
=> Start MySQL from XAMPP control panel
*************************DONT DELETE ibdata1 FILE*************************