Why can't I download Minecraft?

I've been going at this for two weeks now. I've bought the game, I've downloaded it on another computer, but my computer at home literally refuses to let me download it. I've asked this question before, and someone said that my anti-virus was stopping it, so I needed to pause it, then download it. But I don't know where, or what the anti-virus is.

I thought it was windows firewall, but it won't let me disable the firewall, and then I try to update the windows firewall settings, and it does nothing. Absolutely nothing. I bought and downloaded it from Minecraft.net, the actual site, but when I click it, it goes to the bottom and says "Failed - Virus scan failed". I've been trying to figure out what it means, but I can't find anything.

You probably haven't got Admin Privileges on your home computer for what ever reason, if you seriously want to play it that bad, just grab a memory stick, copy the minecraft.exe file onto it (it you want to copy your world as well go to (assuming you only have one HDD) in your file explorer C:\Users\YOURUSER\AppData\Roaming\.minec… And just copy the "saves" folder.