The default mouse click for opening applications is to double click. This can easily be changed so that you only have to click your mouse button once to open any application.
1/ Click Start button.
2/ From the Start menu click, Control Panel.
3/ In the Control Panel window click on the Folder Options Icon.
4/ In the Folder Options Window on the General tab look for the section marked 'Click Items as follows'.
5/ Left click on the small radio button (a small dot will appear) next to the option 'Single click to open an item'.
6/ Finally click the Apply button followed by OK to Exit.