Our female cat is 5yrs old (she's fixed) and has been the perfect
indoor-only house cat for the last 5 years.  But about a month ago she
started having "accidents" outside of her litterbox - on the floor,
chairs, windowsills.  Now for the last two weeks she completely
refuses to poop in her litterbox.  

I caught her a couple times & it's freaky: she starts zooming around
the apartment dropping dookie-dogs as she goes.  She'll jump on things
as she runs and drop nuggets along the way.  

My wife thinks it's a behavioral problem, but I find that hard to
believe since she's been so perfect for so long.  Plus, she still pees
ONLY in her box.  I've tried setting up a second box for her (which
she likes to pee in as well), and have been locking her in the
litterbox room (spare bedroom, NOT a closet) with her food & water
during the day, but she still refuses to poop in her boxes (prefering
the floor, my computer desk, the windowsill instead).  

It's pretty horrible.  I was wondering if anyone else has had a
similar situation arise?  I'm trying to talk my wife into taking her
to the vet on Friday just to get checked out, even though the cat acts
perfectly normal the rest of the time.

Thanks,

Anthony