how to install LO in Windows 8.1

The download of the .msi file went correctly.
When starting this file, either from downloads or from desktop and permitting to make changes to the harddisk I get a screen which suggests that the program is installed in about 2 seconds.
Then it says: Finnish, but after that the program is nowhere to be found.

What is wrong?

Did you get the User Account Control prompt? Where it asks you "Do you want to allow the following program to install software on this computer? And did you answer yes?

yes and yes

same problem here
please help !