Try
http://localhost/
In the left menu click on
Status and see what is
Activated
You have to imagine that we are not sat in front of your computer.
So you have to tell us everything you see and everything you have tried.
We have no way of knowing what's happening unless you tell us.
Look in the mysql error log just after you have tried to start it and see if there are any clues:
xampp\mysql\data\(yourcomputername).err
Drag the file into your text editor (notepad) and see what it tells you.
It might provide a clue why it is not starting.
Are you using the XAMPP Control Panel to start the components?
Try starting mySQL using the
xampp\mysql_start.bat and see what the message returned is.
If you can't understand it paste it here what you see in the command console window.
Click on the little icon top left of the console window for a drop menu of Edit commands.