Good afternoon (or evening) to all again
With the assistance of some guys from another local forum, I found the causes of the problem and the solutions for them. I am posting them for your guidance. Here we go:
A. For a ripped Blu-Ray, it is necessary this to be done in ISO files. This can be selected when using AnyDVD HD. Thenafter, and when the movie has been stored in a hard drive, a virtual drive is necessary to be used, since PowerDVD DOES NOT reproduce ISO files, if these are not played by a driver. In other words, the ripped movie will be "seen" as a physical disc in a physical drive, if the files in it are ISO and there is a drive, no matter if this is physical or virtual. The best virtual drive is the Elaborate Bytes Virtual CloneDrive, which is free and can be downloaded from http://www.slysoft.com
(the site for AnyDVD).
B. For the ripped DVD I was making the mistake to open the .VOB files. Instead, I went up one level and found the VIDEO_TS folder (which contained all .VOB files). When I hit PLAY on it, the movie came to my screen with all its menus, bells and whistles and I could manage to see and select subtitles, select audio languages and format, etc.
Have a good afternoon.