MySql start as service even without installing it

[sham08]

Hello.I've recently install XAMPP 1.6.7 and when I open the XAMPP control panel,the MySql service check box have been check even I haven't installed it as service.And worse,when I click the start button,it won't start.It keep saying 'busy'.Oddly,if I unchecked the service check box it goes well (start normally).Seem Apache didn't encounter such problem.And other problem is how do I configure the security (username and password) for both Apache and MySql?Thanks in advance for anyone who wish to help me.Don't let me walk through the dark,please.Last time I posted through this forum but to no respond.I really need help.