Can you execute a VBS file as a screen saver? I have managed to rename cmd.exe to *.scr and this works, but I need to be able to run a VBS file as the screen saver if this is possible.
No, this is not possible.
In Windows, screen savers (*.scr files) are a special type of executable (.exe) file. That is why renaming a program like cmd.exe to cmd.scr causes it to sort of "work" as a screen saver. In particular, screen savers respond to certain command line switches (or parameters), which is how the OS gets them to do things like show the configuration dialog or display a preview.
But you can't compile VBScript files into executables, so there's no way to make this trick work for them.
You might be able to migrate the VBScript code to a VB 6 application, which you could then compile into an executable and run as a screen saver, but I can't imagine that this would be worth the development time. If you're interested in such a thing (and can get your hands on an old copy of VB 6!), you can probably find several how-to guides online, like this one.
But I'm honestly having a hard time imagining why one would ever want to run a VBScript script as a screen saver, or what it would display on the screen. You don't have very much control over what gets displayed on the screen, and you can't call down to native Windows API functions from VBScript. You'd end up relying upon some external library, so you might as well just use that library in the first place.