I just finished a great book: Heir Apparent by Vivian Velde Vande.

It takes place in a future where virtual reality games are so realistic you feel like you're living the game. Giannine receives a session in a virtual reality arcade for her fourteenth birthday and chooses to play the game Heir Apparent. While playing, a protest group sabotages the machinery. Now she has an added incentive to win -- she needs to in order to save her life.

Here's the review from School Library Journal:

Giannine Bellisario is about to celebrate her 14th birthday. This year, she actually receives a present from her father on time. It is a gift certificate to any Rasmussem Gaming Center Virtual Reality Arcade. Crossing a picket line formed by CPOC (Citizens to Protect Our Children) to enter, she decides to use her certificate for a total-immersion game called Heir Apparent. The object is to be crowned king. When the demonstrators damage the center, the protagonist is on her own and must complete the game successfully in order to escape permanent brain damage. Ghosts, witches, wizards, and magical tools help her as she races against time and faces many setbacks. Challenges range from barbarian attacks and peasant uprisings to a giant dragon. In addition, the half brothers and the hostile queen have treacherous plans to keep the crown for themselves. This adventure includes a cast of intriguing characters and personalities. The feisty heroine has a funny, sarcastic sense of humor and succeeds because of her ingenuity and determination.