This may help you-
Apache, MySQL, and FTP 'Detected With Wrong Path' using XAMPP on Win7
Or if your IIS server is already installed
Just disabling IIS Express & it wasn't enough, to free the port 80, you must disable "WebClient" and "Web Deployment Agent Service" services. Go to Control Panel > Administrative Tools > Services.
This will solve your all problems.
If it creates problem let me know.