My DD2 Won't Nap - Really Need Advice

[ammama]

Ok, i'm getting to the point where i'm at my wits end with nap time.

My daughter turned 2 in November. She has been napping pretty well for the last year, until a couple of weeks ago when we took her pacifier away. Now she only naps about 25% of the time. She knows that it is quiet time (the other 4 kids here DO nap), and she willingly goes up to her room, and I put her in the crib. She doesn't cry or fuss, but just plays quietly for the whole 2 hours, even if she is exhausted! I really need the kid to sleep - SHE needs to sleep! The afternoons have been terrible, since she is so cranky from lack of sleep.

She wakes fairly early in the morning on her own (7am), we go outside and get quite a bit of exercise (we were at the park this morning for almost 2 hours in -10C weather). Nap time is 12:30.

I'm not sure what to try. I've thought about switching her to a nap mat with the dck's, but she is not a dck, and I don't really want to treat her like one. She has her own room, she should sleep in it. We don't usually have this problem at night, although sometimes, if she did nap for 3+ hours in the day, this will happen at bedtime.

Any advice is appreciated