I understand this wasn't an easy process for you, @Tidler.

I'm here to provide some info about the script error and how to remove the banner ads.

First, QuickBooks Desktop uses Internet Explorer (IE) to download updates and display most of the windows in the software. Thus, you'll have to use IE as the default browser. If you haven't already, here's how:

1. Open Internet Explorer, and then click the Gear icon ⚙️.
2. Choose Internet Options, and then pick the Programs tab.
3. Under Default Web Browser click the Make Default button.
4. Click OK to confirm.

Please refer to this article for more info about the steps above: How to set IE as the default browser.

Then, let's ensure to configure IE to prevent the script error. I'll guide you with the steps:

1. Open your Internet Explorer.
2. From the Command Bar, choose Tools.
3. Pick Internet Options, and then select the Security tab.
4. Click Trusted Sites, and then select Sites.
5. Choose Add this website to the zone field, enter *.intuit.com and click Add.
6. In the Trusted sites window, uncheck Require server verification.
7. Exit out the Trusted sites window, and uncheck Enable Protected Mode.
8. Close the browser to make sure to apply the changes.
   
   

Second, the banner ads are designed to suggest you on how to optimize your QuickBooks experience. Since they're affecting your navigation, you'll want to click the X or No, thanks button. 

Also, you can turn off these pop-up ads from the Preferences page. Here's how:

1. Got to the Edit menu, and then select Preferences.
2. Pick General, and then put a checkmark on the Turn of pop-up messages for products and services box under the My Preferences tab.
3. Click OK to save the changes.

In case you're unable to use some programs or files or see an error message, you can configure your Windows firewall to fix it. Check out this article for more details: Configure firewall and security settings for QuickBooks Desktop.

I'm around in the Community to help if you have more questions about managing your browser and ads or anything else related to QuickBooks. Take care and stay safe always.