Both the MDK games can be found here: http://store.steampowered.com/search/?d ... _order=ASC
You can buy MDK for 9.99 USD
MDK 2 can be purchased for 9.99 USD as well.
Or you can purchase both games in a bundle for 14.99 USD.
Note: They have been updated to work with current operating systems(Windows Vista, Windows 7), but you may encounter graphical errors. If you do, just notify me and I will present you with the solution that has worked for me, and many others.