Manual 4.0.1 to 4.0.0 reversion?

I attempted to update to 4.0.1, there was some kind of error and now many things are messed up. Essentially because of missing DLLs, the irony being that I figured out the problem and it wasn’t related to the update at all. Is there any way that I can revert back to version 4.0.0 manually? Because I still have the 4.0.0 folder with all the required dlls and such…