In your situation, you may need to do a clean reinstall of the app. While you may have already attempted a reinstall, we would need to remove all the old files first as there could be corruption.
- Uninstall the Blizzard app
- Next open the temp locations and delete any Battlenet and Blizzard folders you see in each location. Press Windows Key + R and type:
• %LOCALAPPDATA%
• %APPDATA%
• %TEMP%
• %PROGRAMDATA% - Finally go ahead and reinstall the app from here. Make sure you run as Admin.
If none of that helps, then it’s likely there is something on the PC blocking the install or a networking issue. If you have any antivirus software, uninstall that and then restart the PC to test the Blizzard app install.