Programs on your PC, such as MED, use many other system libraries and drivers. If such a system file, like DirectX or your video driver in case of MED, is faulty or missing, the program can not work. A missing file leads to an error message, a faulty file to a crash.

For finding out what's wrong on your PC, MED writes the text files "med.log" and "med.txt" in its folder. They can contain information about what's wrong or missing.

So you need to post the content of both files here, otherwise we can not help you. You can open them in any text editor. "med.txt" may be empty when the crash happens before something is written into it.