I need help pls

Hi, I downloaded d2loader and when I replaced the Diablo.exe file it messed the game up, so whenever I opened the file up it had an error, so I deleted the file and now whenever I want to play Diablo II I have to open game.exe. Is there anyway to get Diablo.exe file back without uninstalling Diablo and installing it again? One more thing, is there anything that allows you to be able to play without the CD? thx