http://www.jimmys-adventures.net/adventure-island-game-online-free/
Where can I find old comp games (Adventures of Laura Bow, Monkey Island, Loom etc) online to download free?
Old unsupported software is termed abandonware. You can go to sites such as The Underdogs and download older games such as what you mentioned.
Read more about it on Wikipedia.
Adventure Island + Pinball hacks for 8-bit Nintendo (NES)