When i click on xampp_start.exe ..
and when i am stopping it, in the window is written: Can't find mysql/data/mysql.pid or apache/logs/httpd.pid
i dont know what does it exactly mean
Thats correct, thats a console program. The default way to start/stop XAMPP components is the XAMPP control panel.
You can find the xampp-control.exe in your \xampp\ folder.
In your XAMPP version you have the choice which control panel you want to use, the standard control panel or the new control panel v3 as beta (last one is far more useful and will be the next default control panel in later XAMPP versions).
So, start the control panel of your choice and then start the components you want with their "Start"-Buttons.
It is a good start to read the following documentations first (where you could have find the different ways of starting the XAMPP components too):XAMPP for Windows #The PracticeXAMPP for Windows FAQ
And the readme_en.txt file in your \xampp\ folder