error code 21 - can't install CC even with all requirements

Hi guys. I just abandoned my cracked Adobe Suite finally, but got a little frustrated now that I tried multiple times installing CC, PS and AI using the installer downloaded from Adobe website and all of them show me this error code 21, which seems to be an error of incompatibility with my computer. It just happens that I have a notebook with I5, 1TB hdd, 8gb ram, Windows 8.1, so I really don't know how to proceed.

What I already did:

- First of all, as soon as I paid for my subscription, I uninstalled all adobe apps I had. Had a little trouble uninstalling Creative Cloud app though, so I used the "creative cloud unninstaller" available in adobe's website and it worked;

- Then, using CCleaner, wiped out any garbage that could be left from Adobe apps unninstalling. Also deleted manually folders in Program Files (x86 and 64), App Data, Common Files, etc;

- Restarted my computer several times;

- Tried using compatibility mode in the installer, didn't work either;

- When exploring Apps in Adobe website, opening any of them, it shows in the right side "compatible", as if the website itself could compare my pc specs to the requirements;

Anyway, tried many ways to install and none of those worked, so I'd appreciate some help.