Not knowing what system you are running, I may not be able to help. But...
1) How do I check the amount of memory installed
without ripping open the
beast?
Under the apple symbol in the top left of the menu bar is an "about this
macintosh" option - that should give you memory, memory usage, and the
version of the OS. This is under system 7.1, but it should be on most (if
not all) the versions of the OS.
2) The machine was running some programs (Chess, for
example) and suddenly
refuses to do so, claiming, "xxx K needed to run this program. You have 512
K). Customer doesn't know how much was installed. Might this be a
configuration problem, or has it lost contact with half its RAM? (and it
hasn't even hit 40 years yet!)
I haven't encountered that problem yet. The Mac plus should have more than
512k as standard. (mine has 2 meg, but that was expanded). Anyway, when you
highlight a program, but don't start it, you can go to the file menu and
look under the get info option. That will tell you, at the bottom, what
the suggested memory size is, and what the minimum and prefered sizes are.
Changing these may solve your problem, and if not I can only assume that it
is, indeed, hardware related. I don't think there are any software
settings for memory, but I imagine there are the usual switches on the
motherboard - unfortunatly I don't have that much info.
Hope that helps,
Adam.