C5 should run fine on that system.  I tend to do a lot of work with both C5 Pro and poser 6 so my systrem is a bit heftier to import and handle multiple poser characters.  You might benefit from some more RAM though.

C5 has a very forgiving learning curve and is easy to use straight out of the box.

I know what you mean about arthritis.  I had to give up music and a few other hobbies because of it.

I have CS2 but I usually use Paint Shop Pro from Corel more.  All of the features and w lot less expensive.