Everybody who know things about computers please help?

what do 0 bytes free of 5.53 GB UDF mean?? i'm trying to play my sims 3 but i dont think i have room for it...and i will like to make room for it but i dont have any idea what i'm doing....i already deleted stuff that i dont need on the computer but when i go to start then computer then look at the DVD RW drive with the sims 3 in it..under it it says 0 bytes free of 5.53 GB...whats the problem please help