Error 80070643

I was able to solve the problem yesterday myself luckily. Apparently there was something wrong or broken in the SL2 Program Files folder. Here's the steps I followed for anyone who's having the same problem:

1. I installed the SL2 version/update I had in my computer before trying to update (in this case Update 5, but it could be another) in ANOTHER computer.
2. Once properly installed (I checked if I could open Storyline properly before this), I copied the SL2 Program Files folder from that other computer in a pendrive.
3. Back on my computer I pasted and replaced all the archives in MY program files folder with the ones copied in the pendrive (which came from the other computer).
4. That should make SL2 open again and work (with the previous update I had), which it did.
5. Then i proceeded to install the new update with all windows closed just in case, and always running as administrator.

My case was #00641506 and Renato told me that what I did would 'rebuild the folders in Program Files and fix the problem'. That was it for me luckily. Hope it helps! 

Thanks anyway.