HELP WITH SCHOOL //c

[euc@cpva.saic.com]

In our elementary school, there is an Apple //c with what appears to be a
composite color monitor made by NEC.  The display seems like it is shot, that
is the 40 column characters have become illegible except in CAPS mode. 
Assuming the problem is a bad monitor, and we have to buy a new one (if one is
still made--have not looked into that yet!), can we buy something that will
give a better resolution than 40 columns, or is this controlled by the video
card rather than the type of display?

Assuming the diagnosis of a bad monitor is all wrong, anyone have any ideas? 
Also, what kind of information would you need to make an informed guess?

Unfortunately, my wife, the school volunteer, and myself, are both IBM PC types
and no nothing about Apples, new or old (except the new ones are called the
Apple Lisa :)  I mean McIntosh).

Thank you in advance for your assistance.

Charles