Battle.net Installer Crashes Up to 65%

Yesterday some friends asked me to install Heroes of the Storm, and the installer never finished checking the installation space. After trying everything, one of the tutorials told me to install Battle.net: now I can’t even install Battle.net.

The updater keeps trying to update, gets to 65%, progresses a little (random values) and then goes back to 65%. I saw that several people had this problem for years, but NO SOLUTION seems to work: Is there any reliable reason/tutorial for this kind of problem? Until a few months ago I was playing WoW normally…