Help about installing Nuke 8.0 v5 (I'm a mess)

Hi guys!

Originally I've posted this in the respective thread but got no answer. I still need some help, I'm a mess. I tried to install Nuke in Windows 8.. I thought it worked and when I opened it I've found the license failed. I tried to fix it but it didn't work. Then I decided to uninstall, delete the folders after uninstallation and make the whole process again.

I've re installed the nuke, but when I tried to install the FLT, it says it's already installed and I've got to go back to uninstall it, but I already deleted the folders, and don't know what to do to clean it before to install nuke.

Thanks!