Basically, an MDS/MDF File is a DVD image file, so what you need to do is burn the image onto DVD and then run it from there.
1. Download a program called
Alcohol 120% here..
2. Run Alcohol and select Image Burning Wizard > Select Browse > and find the MDS file in your directory. Click Next and then Start to burn it onto DVD. Once it's finished, just load the DVD into your PC and there, you will have the game.
If you do not have a DVD burner, then don't worry.
1. Just run Alcohol, select Virtual Drive, and then click OK. This will create what's called a virtual drive, which is basically a "drive" which is recognised by the PC, and therefore can run/load things just as real drives do.
2. Close Alcohol and then go to where the MDF file is > Right Click > Mount Image > Select the virtual drive which you've just created.
3. A window will pop up with all the files included in the DVD image, allowing you to install/run the game.
P.S. scan the files for viruses, spyware, malware, trojans etc. before installing.
P.S.S. buy your games! :thumb