Hi S., I completely sympathize. We had to transition our son when he was 2 years old to a big boy bed in the other room (out of his crib and the nursery room), because I was pregnant and expecting another baby soon - and he wasn't too happy about it at first. What worked for me was transitioning him gradually - it's hard at that age because they can't talk as much yet or communicate if something stressful happened during the day - or if they're having nightmares and are afraid of falling asleep by themselves, etc. I think a nightlight is a good idea, too.
What we did with our son was give him a calming bedtime routine, hugging him while reading bedtime stories, etc. and then after we turn out the lights, we would sit near his bed, and talk very little (or not at all if he tried to keep talking to us). And then the next week, we would start sitting a little farther away from his bed and closer to the door, but he could still hear our voice. We would always leave the door halfway open - and then we would sit right outside his door, etc. It took a little while, but I felt that this worked better with our child than leaving him to cry it out. Personally, I think it would be terrifying for a child to be in a dark room with the closed door, esp. if they're trying to communicate something to their parents but don't have the words to express it yet. We found the book "No Cry Sleep Solution" for Toddlers by Elizabeth Pantley really helpful, too. And maybe if she's 2 years old, maybe you could re-create the room into a "big girl" room for her with some new decorations or move her to a toddler bed as a new "fun" bedtime routine? Hang in there! =)