Well Sibylle
It sounds like your browser has been got at and is possibly compromised, also Stopzilla is not an anti-virus software it's an anti-spyware. So, if all you have is Stopzilla then you must get yourself an anti-virus program.
As for your browser, which I am guessing is probably IE 7 or 8, I would suggest that you uninstall and delete all traces of it and clean out your registry. Then do a fresh (clean) reinstall.
If this does not work then uninstall it again but this time install another browser.
UK Bob |