Registry invalid message errors are not seen as much these days as they were a few years ago. Usually a “registry Invalid” is the result of an entry made into the registry that is not compatible with that registry.
It is noteworthy all Windows operating systems have registries, even the very early ones and yes, Windows 7 has a registry as well. It is also noteworthy that there many registry cleaners around these days that are not at all helpful and may actually even be dangerous to your computer! However, using a good registry cleaner is necessary simply because keeping corruption out your computer’s registry is necessary.