This is worse than any other who has taken over the searchengine. Would be glad for any help - or maybe I should just remove and reinstall Firefox?
You can use the SearchReset extension to reset some preferences to the default values.
Note that the SearchReset extension only runs once and then uninstalls automatically, so it won't show on the "Firefox > Add-ons" page (about:addons).
If you do not keep changes after a restart or otherwise have problems with preferences, see:
Another place to check. If in doubt, disable everything nonessential or unrecognized:
orange Firefox button (or Tools menu) > Add-ons > Extensions category
Thanks to both for answer. I deceided to un/reinstall Firefox, at least it removed Qvo6 from the startside, although It is still there somewhere in the background.
Make sure you have no user.js file in your firefox settings and there are no unknwon programs in control panel. This is typical reasons why one can't reset search engines.
You should really scan your computer with AdwCleaner and Malwarebytes because usually Qvo6 comes bundled with adware and PUPs. See this:
Supplemental security scans are a very good idea!
As mentioned in the above page and in another thread earlier today, the software adds an unwanted URL to your Firefox program shortcut.
If you right-click the shortcut > Properties, then look at the "target" what you want for 32-bit Windows XP is along these lines:
"C:\Program Files\Mozilla Firefox\firefox.exe"
with nothing after it.
If in doubt, copy the whole line and paste it into a reply for analysis.
Edit: The above apparently was fixed by uninstalling/reinstalling Firefox. But if the problem returns, you'll have the information on where to look.
Thanks for the suggestion - I still get a clean startside after reinstalling Firefox. I hope it will stay that way, as I am not a "firefox" in use of edb myself.