Why does it ask me for disc when i play crysis?

hi, i use to have crysis through using the disc when i play, but when my cd drive got messed up, i decided to just get it online and have it in my hard drive instead. ive been playing like that for weeks now. all of a sudden today when i turn on my pc whenever i click to play it it tells me no disc inserted please insert original crysis disc. why did it do this all of a sudden? what can i do to fix it? im not sure what the cause is since i didnt do anything on my pc. thanks.

ill try that...reinstall the game without the disc...that was the point of the question ;D