II GS Memory & ProDOS

[wcbland@pacifier.com (Bill Bland)]

My II GS has the Applied Engineering GS-RAM board. When I could get
the machine to run, it would report something like 1.6 MB. Today, I
picked up another memory expansion board, an Apple II GS 670-0025-A,
and noted that it has four 256K chips soldered on the board (150 ns)
and slots for another 24 chips. So, I went back and looked at the
Applied Engineering board. *It* has 3 rows of 16 256K chips. That's
12MB, right? So, why the low reported number?
I don't need both of these memory cards. Can someone advise me as to
their value?
Which brings up a final query. I haven't yet been able to afford a
Focus hard drive card. So, I've been booting with Disk 2, the System
Disk. It worked well until tonight. Now, I get "Unable to Load
ProDOS." What's  happened?
Finally, is there a way to quiet the fan in a Kensington System Saver
II GS? I can't figure out how to get inside the case to install a new
fan, in spite of removing the two screws. It's noisier than heck!
Thanks,
Bill