Glad you got your system back. It looks like there are remnants of Avast still there. To get rid of it I would try, in this order:

1. Windows running in normal mode: look for Avast in Control Panel...Programs and Features, and uninstall it from there if it's present

2. Restart your computer into Safe Mode: https://support.microsoft.com/en-us/windows/advanced-startup-options-including-safe-mode-b90e7808-80b5-a291-d4b8-1a1af602b617 . If Avast is still listed in Control Panel...Programs and Features, see if you can uninstall it from there

3. While in Safe Mode, run the avastclear.exe program you got from Avast. According to https://www.avast.com/en-ca/uninstall-utility , it needs to be run in Safe mode. If you tried running it earlier in normal mode it may not have completely removed everything

>I am now typing this on the Windows 7. I found that the PC has an auto restore point on January 15th. I used it to restore. It took some time. In the end it said that it could not restore all system file. But...browser now works and the Avast is gone. Seems to be gone completely. I will continue checking if the Avast is somewhere there but so far, nothing.
>I know and I listen to what you are saying. I have to be extra careful on Windows 7.
>Thank you for bringing up the restore point.
>
>UPDATE. You can't get rid of Avast. When I rebooted my PC, it comes up with the message that Avast needs to restart the computer. I selected it. But it hangs during restart. So, it comes back with the same message, on the next reboot, that "Avast need to restart the computer." So I selected to Postpone until next century.
>We will see how well this strategy will work.
>
>>If you're still using Windows 7, that's a big security risk right there. You should not be browsing the public web with a W7 PC. I have a few clients still running unsupported Windows OSs on a few client computers, because they have hardware and/or software which can't be upgraded and which will not work on supported versions. But aside from that I can't think of any other legitimate reasons to still run old versions of Windows.
>>
>>On W7 the free Microsoft AV was MSE: https://en.wikipedia.org/wiki/Microsoft_Security_Essentials#Discontinuation . Apparently it's still available and the wiki claims it's supported until 2023. Third-party AV vendors typically don't announce any time period during which they will support their products running on unsupported Windows OSs; if you read the fine print they'll typically say "support can be discontinued at any time, without notice". I suspect in practice, their support will end as soon as a serious vulnerability is found in W7 that MS won't patch.
>>
>>Another option could be to check your system's restore points. If the Avast Premium installation was playing nicely it might have created one prior to installing itself. If so you might be able to roll your system back to that point.
>>
>>>First, thank you for your detailed reply. I did pay for this product. But at this point, I am more concerned about being able to use my PC than about money.
>>>
>>>I plan to uninstall Avast - cleanly - using they avastclear.exe But I will probably backup my OS completely, using the default Windows 7 backup (this is Windows 7). Then uninstall Avast. Hopefully, if after uninstalling Avast, I still have a problem with this PC, I can restore from the backup.
>>>
>>>The problem with this version of Avast is that there are SO many choices that it is mind bugling. Confusing too.
>>>
>>>
>>>>Prima facie it looks like the Avast "upgrade" is causing your problems.
>>>>
>>>>If you've paid for the product you should have some way (e.g. activation code) to reinstall it if necessary.
>>>>
>>>>In your situation I'd test by completely uninstalling the product, and also running any available Avast complete cleanup/removal tool. Make sure if you do that, that the built-in Windows Security gets re-enabled. Restart if prompted, and even if you're not prompted.
>>>>
>>>>My policy with purchased software (all kinds, not just AV) is that it should make your life easier. If I pay money, and it makes my life more difficult, I ditch it and get my money back. This is especially true with AV, since you're granting it full godlike privileges over your computer - even more than you think you have. The first priority (yes, even ahead of keeping you "secure") is to keep out of the way of legitimate use; if it can't do that, it casts doubt on how well it can do its other purported functions.
>>>>
>>>>In my experience, as long as you follow reasonable cybersecurity practices, you don't have teenagers also using your computer, and you're not browsing dodgy web sites, then the built-in Windows Security works fine. It has by far the best record for not interfering with legitimate use of your computer.
>>>>
>>>>One of the greatest cyber threats these days is visiting a compromised web site. I recommend using a locked down browser such as Firefox with NoScript for general web browsing. That doesn't always play well with e-commerce or government web sites but you can use Chrome or Chromium-based Edge for those. I'm not a fan of AV plugins for browsers unless the computer is being used by someone who can't follow reasonable cybersecurity practices. Plugins are another layer of complexity and can break the browser, or interact badly with other plugins or extensions you may have installed.
>>>>
>>>>>Hi,
>>>>>
>>>>>Today, Avast agent (the AV software I have been using) made me update their software to the Avast Premium. Now, after I installed Avast Premium, I can no longer use Chrome. Any URL I enter in the browser address goes nowhere. And very limited use of Firefox. Oddly the IE works.
>>>>>
>>>>>I tried to shutdown/disable Avast for 10 minutes but, still, Chrome does not work.
>>>>>
>>>>>Could this be a coincidental issue with Avast? Or, I should try to uninstall Avast all together?
>>>>>
>>>>>Any suggestions?
>>>>>
>>>>>TIA