Aw sorry to hear! The game runs through SteamVR, which should auto-launch if you double click the .exe (and oculus should also start).
All grey-screen problems so far were solved by turning around (shame the OP never told if it worked). My fault for using the monotonous grey! So there’s nothing behind you in VR?
If not, I’m at a loss, I’m sorry. Let me know!