Yes, it truly sucks when naps cease after 24 months. What I did when it happened and I need some shut eye.
Make sure your TV room is secure both for safety from stairs and things your little girl can mess with.
Make sure you have a DVD player and get some Baby Einstein videos, then watch them a few times till she is digging on them.
Play the video and she will learn animals and to count among other things while you lie on the couch and catch a 15 minute power nap here and there. You won't be totally unconscious and totally oblivious to the world, at least I wasn’t, and were able to respond to noises.
It is not ideal by a long shot to do this but if a day or 2 of ½ day preschool isn’t in the pocketbook then you got to do what you gotta do!
Good luck and welcome.

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1. How old is she? Naps were refused just before my oldest turned 4. Now, he has "quiet" time when he can sit on his bed and read books or play a little on his own. This lasts for a little more than an hour, and he still pokes his head out every 20 minutes or so.

2. Reduce sugar intake, including juice. Water it down more if you can't break the habit.

3. Reduce or eliminate TV and/or computer time.

4. Get her good and tired every chance you get. Play, play, play. Exercise: dance, tumbling, skating, playgrounds, playdates.

5. Make sure her room is still conducive to sleep: lighting reduced, quieter/softer music, fewer toys out/accessible.

6. Read to her more before naps and bedtime.

7. Could be other explanations: nightmares? noise? overstimulation before nap/bed?

i think we all can agree here that when it comes to the first three or fours years you have to deal with your child and phases... like teething (a hellish phase) or napping (i used to nap w/ one of my sons but that created a monster who couldn't nap by himself) and general growth spurts where their brain explodes and their limbs grow and their appetite increases.. bottomline is that every kid is a snow flake and there isn't really any "standard" per se although don't get all hippie and let the "anything goes" shit go on for too long. give them boundaries, be stern and, yes, you will have to drink lots of coffee but not - hopefully - for the rest of your life.

summation: hang in there fella, this too shall pass

Don't get locked into your routine. Try a 3pm nap. Or even a 10am nap. I think you'll find that if you vary the routine, you will capture the perfect window. The nap can be thrown off because she's over-tired from the previous night of restless sleep, and the restless sleep is because she is over-tired from not napping. It's a vicious circle.