Re: I have a mac oOS X which came with photoshop CS5.1 ready installled in May 2011. Recently it has failed to appear on my icon bar and it now tells me that some of the application components are missing and to reistall. As I bought the mac with the inst

Ok, then the university should have kept the disk and serial number (or equivalent) on your behalf and you need to contact them.

It is entirely normal to need to reinstall/repair software and you either need the stuff or a way of getting it done.