@Jaka,
Sorry to hear you are having problems. You say that it works in 3.0.2, but you also say that when you run it you do not get a repair choice.
What Version was the one you have before version 3.0.2?
I suspect that you need to run the version that caused this problem which is more than likely version 2.2.0
You should see the proper selections and then follow the guide above.
If all else fails you do have an option to use though, (because it will never work right until it is repaired) and that is the Windows Installer cleanup located here:
http://support.microsoft.com/kb/290301
<snip> from VirtualBox HOWTOs.
If you are experiencing installation problems on Windows hosts you might want to run the Microsoft Installer Utility. It's available for free here: support.microsoft.com/kb/290301 It does not uninstall VirtualBox itself but provides a way to clean the registry from leftover data of former installation procedures.