Open the program you wish to open the files with [in my case IrfanView] and in it's file types selecter [ in options or preferences usually ] select the ones you want to open in that program. You should get a message that these are set to CS2, say you don't wish to keep that or whatever and they should open in that app now. CS2, on install if you go automatic, will hi jack all file types it reads I've found.

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again