After update to V 6 searches go to "signalsearchsystem.com" can not find any reference to this anywhere on the internet. What happened?
After update to Firefox version 6 any Yahoo search generates a normal list of web sites. Selection of any of these websites route me to signalsearchsystem.com which then routes me to advertising sites and / or Google !
Wšykne wótegrona (2)
Sounds like a search hijacker. Try scanning your system for malware.
Yep. Try a scanning first. But if you fail, you can also try a manual removal: http://blog.teesupport.com/remove-signalsearchsystem-com-uninstall-signalsearchsystem-com-manually/