I couldn't find any specific searchqu removal guide in German, but these removal instructions are really straightforward:
To uninstall the Searchqu from Computer
1: Click on Start Menu and Click on Control Panel, and then:
2: On Windows Vista or Windows 7, go to "Uninstall Programs" under "Programs and Features ":
In XP it is Add/Remvoe Programs.
3: Select the Searchqu you wish to uninstall from the list and click "Uninstall":
4: Follow the steps of the uninstaller application:
To uninstall the Searchqu from Firefox
1: On the Menu Bar, go to "Tools" -> "Addons":
2: Select the Searchqu you wish to uninstall from the Extensions list - then click "Uninstall":
3: When prompted to do so, restart Firefox:
After this if you are still see the Searchqu
Press on Windows Key and R key together on the keyboard
Now you will get a Run Window. Inside the Run window Type REGEDIT and press on Ok.
Now you can see a Registry. (Be Care Full While using registry)
Do note that editing the registry incorrectly may cause your computer to become unusable.
HKEY_LOCAL_MACHINE\SOFTWARE\Searchqu and delete Searchqu
HKEY_CURRENT_USER\Software\Searchqu and delete Searchqu
And restart the computer. Now it will be gone.
Don't Forgot to change your home page to www.google.com after this fix