If there is no progress bar to be seen, it might be a rare InnoSetup bug caused by conflict with other running application.
First thing to try is to close unnecessary programs running in the background (even Skype can cause that) or restart the OS and then try installing again.

If the problem persists, go to your Temp folder (C:\Users\<USERNAME>\AppData\Local\Temp) and find the newest 'Setup Log <date> ####.txt'. Open it in Notepad, scroll down to the very bottom and you should see what interferes with the installation process.