On my brand new Lenovo laptop today. Did all my Windows 10 and Intel Chipset updates, uninstalled free 30 day McAfee Live Safe, went to avast.com to download free antivirus in my Chrome browser and got a 404 error. Grudgingly used Microsoft Edge browser and the download worked perfectly. Wondering what the problem was in Chrome.
Best to ensure all A/V’s (or any crapware) is uninstalled: https://singularlabs.com/uninstallers/
Which web address did you visit ???
You can download the latest version of Avast from here:
https://forum.avast.com/index.php?topic=224223.0