Norton has many false positives I believe. And many other things.
Either way, use Avira or, even better, Kaspersky. Also Bitdefender, etc., just choose any except Norton and McAffee. Both those have caused problems. :\
Only choose one antivirus though! You can have 2 or 3 installed, as long as one is deactivated and the other is active. If both antivirus are on it may cause problems with the PC. As an additional layer of protection, get MalwareBytes. It's 100% safe as long as you download it from the official website.
Oh, and don't forget uBlock & NoScript, if you have Firefox that is. If you use Chrome, you can use NoScript as well, but if only uBlock was compatible with Chrome... (chromium is the open source program of chrome btw, chrome was based on that, it won't work with chrome)
This went from a download problem to an antivirus thread, but whatever.