Let's try d1x (decent) as an example.
Reading the log-file:
1.) run d1x-rebirth it will create a logfile.
2.) on your desktop double-click the icon "File System"
3.) in the new window scroll down and open "tmp"
4.) find the file "pndrun_d1x.out" and double-click it
5.) read the messages and search for something that goes wrong
Example: Without the <appdata>/d1x-folder it will read "Error: could not find a valid hog file (decent.hog)"
If you find a error-message that it is missing some file, then check the content of your appdata/d1x.
Checking the content of your d1x-appdata-directory
1.) On Desktop double-click the icon of the SD-card where the d1x-rebirth.pnd is on
2.) open the directory "pandora", then "appdata", then "d1x"
3.) look at the files listed there.
When i look at the d1x-directory then i see many files all in lower-case letters. For example "descent.hog" and not "DESCENT.HOG".
If all your files are in upper-case letters (for example DESCENT.HOG), then use startmenu->system->bulk rename
Using "bulk rename":
1) start startmenu->system->"bulk rename"
2) click on the green +
3) go to your SD-card->pandora->appdata->d1x
4) click one time on the first file in the list, then hold the "shift"-key and hold the d-pad down until you reach the end of the list
5) select "open"
6) click on "insert/overwrite" and select "Uppercase/Lowercase"
7) click on "name only" and select "name and suffix"
8) make sure that "convert to: lowercase" is selected
9) click on "rename files"
