Sorry to hear about the missing snake and hope you find her soon. I know there have been a couple threads about this with some good advice.

It happened to me a few times in the past before I switched to solid top lids (they fit on the inside lip) and here is what has worked for me:
1. I know it sounds crazy but if you have a cat, try placing the cat in the room where the snake was kept. My oldest cat was good at playing "find the missing snake". Just make sure you keep a close eye on the cat and that you trust the cat not to harm the snake.
2. In my experience, they almost always stay within a few foot radius of the enclosure. Closets, and dresser drawers were my snakes favorite.
If you haven't already sealed off the room where the snake was kept, try that- hopefully she is still in there. Start at one corner and work slowly around the room, do this one room at a time. I am sure you know just how tiny of a space they can fit themselves in. I think someone mentioned using flour or something, that way you have a visual clue that they are in the room- if she moves about.
Good luck and I hope you find her soon!
Ingrid