Since installing SP2 on my XP operating system, I have been getting
crashes.  Until doing the update, I never had any crashes. The heading
is page_fault_in_nonpaged_area.  The code is
STOP 0x00000050 (oxe16c4000, 0x00000000, 0x805125ca, 0x00000001)

I've searched the net for solutions, but each one looks specific to a
specific computer.  When the latest crash hit, I was logging out as a
user and logging in as administrator.  It also seems to crash only
when I'm logged in as administrator.

From want I see on technet sounds like Windows is having a problem
with your RAM. Check if Windows is see the correct amount of
RAM(should been a spec that came with your computer) then if it is try
running Memtest (http://www.memtest86.com/) to see if you have gotten
at somepoint a bad block of ram. If you know what your doing or have a
techy friend how does you can also try taking the RAM out and putting
it back in your computer.

Hope this Helps