Logic only allowing "external midi" as an option / "Selected drive not found" error

"So, I started up Logic for the first time in a while recently. Created new project, and only "External Midi" was available as a track option. First weird thing. Second weird thing is that there's now sound at all coming from any of my existing projects. When I play them, there is no volume levels showing on the mixer, so Logic isn't even sending any output to my monitors (I tried using the laptop speakers, same result). Third weird thing, is that on my existing tracks, most plugins and FX have a "!" above them. Something has went badly wrong!"

Hey - after having the same issues mentioned above, I followed these steps but still not working for me. I just get an error message saying "selected driver not found"

Can some one please advise me what I should do?

Thanks in advance