So, before deleting files, first try to do what the error message in XAMPP
message panel recommend you to do, using the MySQL backup folder which is
included with XAMPP. So do the next:
Rename the folder mysql/data to mysql/data_old (you can use any name)
Create a new folder mysql/data
Copy the content that resides in mysql/backup to the new mysql/data folder
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)
Finally copy the ibdata1 file from mysql/data_old and replace it inside
mysql/data folder
Start MySQL from XAMPP control panel
And, voilà. No databases lost, no ports changed, no run as administrator,
no force recovery, no kill mysqld process, no restoring from previous versions,
no more errors.