For a start Windows copy & paste is a poor way to transfer files from a DVD.
I've had this corrupt files that a DVD copy program worked fine when it copied the files from a DVD.
Kerry56 made some good suggestions but I would try ImgBurn in "Build" mode if you want to rip the DVD to your harddrive as it is. ImgBurn is made by the same author as DVDDecrypter but is current.
If you have a conversion program you like or are familiar with that may be your best option for the conversion. Once you get your DVDs ripped to your harddrive.
I have a couple of suggestions though .
This is a new program .
Use Tools/Join Video Files. Add the .vob files strait from the DVD.
Except the Menu .vob if it has one. Select OK.
Then you will be given several conversion options.With settings for those.
Next another good program it can work directly from a DVD but won't "Index" the files that way. It usually produces a superior result from files ripped to the harddrive. It is AVStoDVD used with the HCEnc 2-pass option . Also select "Muxed Mpeg2 file" . That will create a .mpg file.
These two are what I would try if the ones above fail:
Finally if ImgBurn fails to rip the DVD I would try IsoPuzzle . You need the correct wnaspi32.dll to add to IsoPuzzle's folder but it is available for download in this forum. It creates an .iso file .
You will need a virtual drive to work with an .iso file . If you get to this point I suggest Virtual CloneDrive available from Slysoft.
IsoBuster will create a similar image file to IsoPuzzle.
The trial or free version should be able to do that.
I have the paid version so I'm not sure if you can extract the VIDEO_TS folder with the trial or free version. IIRC those are more limited in function.