There may be a MySQL Windows Service still installed from your last installation that you failed to Stop before deleting the XAMPP folder.
Check using the Windows Service Manager either from the XAMPP Control Panel or from the Administrators menu in Windows.
If you find one then simply disable it - reboot and try again.
You could also try running the mysql_uninstallservice.bat file from the mysql folder, then try and start MySQL again from the Control Panel but do not tick the Svc box.
Often just a reboot will fix things also.
Here are some instruction if you need them in the future:viewtopic.php?p=179699#p179699