Google aqovd for information and removal advice for this nasty virus. I would start with https://malwaretips.com/blogs/remove-aqovd-com/. Malware Tips is usually reliable and effective.

Often, though, Malware Tips will have you Reset Firefox when you might only need to remove an add-on or two and then update a couple settings. When you get to that step, you could try this first:

(1) You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side. No extensions are included with Firefox; all are optional. If in doubt, Disable (or if possible, Remove).

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

(2) To restore your preferred home page and search engine, see:

• How to set the home page
• Change your default search settings in Firefox