The 'empty' error log - That means Apache is not starting at all
What Windows version are you using?
Look in your Windows event viewer System log to see if anything is crashing.
You might want to DL the latest XAMPP Control Panel. AFAIK it should work with your version OK. It has much better diagnostics.
you can DL it here" http://xampp.statusnull.com/CPv3/CPv18.104.22.168z
Copy the files into your XAMPP folder & fire up. It may actually tell you what is wrong.