If you were on a trial version or something...(as in never paid for photoshop)--- (If you paid a replacement disc is probably a phone call away)
Be advised that some of us (definitely Shawn and myself) use:
Paint.net
It just might be the best freeware there is. It was developed (I believe this to be true, Shawn can correct me if I'm wrong) by the guys that made "paint" for Microsoft, but were frustrated in their endeavors by Bill and co.
I don't use photoshop, so I cannot compare the two, but I have been told that in many ways paint.net is as good as photoshop. Personally I have found the learning curve to be somewhat longer than I would like, but once you learn it...like I said, some of the best freeware in existence, imo.
They have a fantastic online community to assist, as well.
I don't know if this answers any question, but just throwing it out there for (possible) consumption.