Acrobat displays only B/W

[Stuart Rogers]

Win XP SP2
Acrobat Pro 6.0
Dell Precision 360, Pentium 4, 3 GHz, 1.5 GB RAM, 14GB free disk space
on C: drive

All of a sudden my Acrobat Pro 6 has lost the ability to display colour.
  All PDFs I open, whether created on my PC or downloaded from other
sources (and known to be colour documents), display in black and white
only.  Printing these docs from Acrobat works fine -- colour as expected.

Cold or warm reboot does not help.

Have I accidentally hit a keyboard shortcut that turned off colour?  Any
other ideas?  I looked through all the Preferences, but I don't see 
anything that looks likely.  Other than that, I don't know where to 
start  :-(

Thanks for any suggestions...

-- 
Stuart Rogers
Technical Communicator
Phoenix Geophysics Limited
Toronto, ON, Canada
+1 (416) 491-7340 x 325

srogers phoenix-geophysics com

"The great enemy of clear language is insincerity. When there is a gap
between one's real and one's declared aims, one turns as it were
instinctively to long words and exhausted idioms, like a cuttlefish
squirting out ink."

— George Orwell