If set to the default setting then it's allright. If changing it slightly doesn't improve the view then it's not worth to do so, and you better leave it on the recommended setting.
That Catalyst thing I don't know, but if you tried it without positive results leave it alone. Based on my experience quite often it's not worthwhile to use other tools, often they cause problems on other ends.
In my opinion you are left alone with the options to wear glasses, using the magnifier-tool, tempering with the windows ppi adjustment or - not reading your screen
Using other software is a tiny option. If the software is reading the settings of OS rather then just assuming the OS is using 96 ppi you will remain with the same problems as you are encountering now. Furthermore if you don't set printareas manually but leave it to the program, the user you send the file to will end up with the problem.
An option to further use excel might be to set up printarea manually as I described yesterday. But I experienced that excel 2002 doesn't allow it the way I offered. Still it allows to setup the printarea by using vba. Are you familiar with macros, or at least in using them?
But first try the way as described, maybe excel 2003 will accept. Afterwards try the attached file and have a look with preview if the set printareas are ok - there should be shown 5 pages only. (Don't worry, the file contains a macro, you can either permit or deny it, it doesn't affect the settings)
Still: What type of paper you've got in use?