OK. Delete the download and use CCleaner to make sure all remnants are gone.
Then redownload it (I'd turn off the firewall/AV) and then when the dl is complete, turn them on again and try to install as Administrator.
If this doesn't work, send an email to email@example.com (mention this thread's url) and keep the auto reply. Don't answer it, but keep it as it has your ticket number. Only answer the signed email from support. It might be Tuesday before they get back to you as the weekend's help requests accumulate.