What says the error.log?
Have you testet to start the apache, over the command-line?
The xampp-control-panel ist not the best way to start the xampp, because it don't show any error messages.
To start the apache: Press Windows-Button and the R-Button on your keyboard. Type cmd in the opened window.
A dos-window will be opened.
Change your directory with: "cd /D C:\xampp\apache\bin" (You have to change the path to you xampp-installation-path
). And press enter.
Now you can type in: apache -k start