Three database server install in my pc.

Question

Hi,

I want to install three database server.
1. mysql
2. sql
3. xamp

mysql and sql databse server run successfully.

but when i install xamp databse server it gives following error

   Problem detected!
   Port 80 in use by "Unable to open process" with PID 4!
  Apache WILL NOT start without the configured ports free!
  You need to uninstall/disable/reconfigure the blocking application
  or reconfigure Apache and the Control Panel to listen on a different port
    
how to install three database server ?

Thanks