OK, great! This makes a solution really easy, altho you have several options that are progressively more involved. The simplest is to quit using the Guillermo account altogether, which should be easy for you since the reason it was created is not really valid. As long as Rafa works OK, there is really no reason to log into Guillermo for any kind of normal use. However, if you do ever have a problem with Rafa's profile, it is my opinion that it is a good idea to have another working user account to log in to that makes fixing it a bit more convenient. There has been a rash lately of people whose profile won't let them log in. If you only have one working user account when this happens, you have to log in to your admin account in safe mode to try to run System Restore or to restore the the profile from a backup in the registry, but sometimes getting in safe mode is a hassle or not even possible--which leaves the only booting/fixing option from other media or slaving the hdd to another machine. You can also remove some malware by logging out of the infected user and working with the other user account. For example, my sister got one of those infections where we couldn't use any system tools like Task Manager, Control Panel, etc. BC's site owner, Grinler, has created a tool called RKill to deal with such things, but there can be several steps to getting it downloaded and installed and running on the affected machine. I logged out of my sister's account, logged into one for myself I had created when setting up the computer for my sister, and ran system restore. That got rid of the problem, but I ran malwarebytes anyway to get rid of any leftovers. This is not going to work for every infection, but in this case it sure saved me a lot of time.
So here are your options:
1a. Do nothing, just abandon the Guillermo account.
1b. Abandon the Guillermo account and create a new Admin account.
2a. Delete the Guillermo account. I was remiss in instructions on how to check the Guillermo account while logged into Rafa. In the users part of Control Panel, click on Manage another account. This should show the user accounts you have control over. Click on Guillermo, and then you should have an option to delete it. When done the icon for the user will be gone from Control Panel and log in screen. You might still see the user folder in Windows Explorer but I wouldn't worry about messing with it or any other remnants. The only hassle with deleting the user is if you have valuable files in the Guillermo My Documents, My Pictures, etc., folders. To save them you would have to go in and change folder permissions while logged in to Rafa. If you need to do this and need instructions, let me know, but, since you say you hardly ever used Guillermo, I'm going to assume there are no files in his user folder that you need which means you can delete the user account and be done with it.
2b. Delete the Guillermo account and create a new spare account with admin privileges. Since you have created accounts before I assume you know how to do this, but, as always, if you need help with it or have any questions, just ask.
3. If you feel the need, we can try to fix the Guillermo account. The first thing I would try is the fix we did in Post #9, but check to see if Guillermo is an admin by following instructions in option 2a--if not it won't work and I wouldn't bother with trying to fix it. Follow the same instructions while logged into Guillermo, but substitute Guillermo where the name Rafa appears. Reboot, then log back into Guillermo and see if things are better. If that doesn't work we can try some things with the tool I mentioned earlier, but it can apparently be bad for your system if used incorrectly, so I won't go into that in any detail unless we know it's needed.
Whatever option you choose, go ahead and do the instructions for it and let me know what you decide and how it goes. Also if any problems crop up while logged into Rafa. If all goes well, I still have one thing more for you to do before letting you go.
The tool I mentioned fixes several sort of stock problems with Windows. I had seen it before I went into my long period of inactivity here at BC, but hadn't had a chance to test it out since I didn't have anything that needed fixing. But just the other day when I saw it mentioned and where it fixed a problem elsewhere, I used it to fix my balky Bluray player on my desktop. Finally got to see the DVD from the 40th anniversary edition of Larks' Tongues In Aspic (my all time favorite KC album, btw) I got for Christmas. Man oh man! Jamie Muir was such a beast!