I am using XAMPP on Win 7 and 8.1 too...it start normally.
Did you try to check the services on Start > RUN > services.msc
Find the service: Apache 2.x. (right click) choose Properties. At form "Startup type" choose "Automatically" and Start the service on.
you should reset the PC and check out again.
Do the same with mySQL.
If you can not solve the problem, use XAMPP Panel to start it manually.