I don’t know why the installer is looking in the Resources folder. My uninstallers are located in C:\Program Files (x86)\DAZ 3D\DAZStudio4\Uninstallers.
You could look for that folder, and run the uninstaller yourself before trying to re-install DS4.
Are you running Windows XP?
There really should not be any problem installing content. EVERYTHING is installed to the My Library folder in Documents. The path is
C:\Users\<Your Username>\Documents\DAZ 3D\Studio\My Library.
The DAZ Studio content will go into the correct folders inside My Library, and the Poser format installers will install to the Runtime folder that is inside the My Library folder. In ALL cases, the path should end with My Library, and not any folder below it.