first off are you using discs or image files and did you follow the defaults on the installation of diablo 2? secondly if you did al the above and it says you do not have it installed on your machine try going into the registry and delete any and all reg files associated with diablo 2 and also try to go to your add remove programs list and see if it shows up there. if it does uninstall then reinstall. if this does not fix it try downloading images from a torrent file and use alcohol 120 to mount and install. this game has no crack so use the lod image to load and play the game. make sure you use legit cd keys or battle.net will boot you. also load the full install so you can view all the videos without inserting the cinematics disc. hope this helps you. if you have saved characters just move that file to another location before you uninstall then paste it back if you get things working right. one more question i should ask is what OS are you using. if all this fails then i am as stumped as you are.