The board at Shell knew it needed to do something, and fast.

A shocking revelation in January -- that the world's third largest oil company had overstated its proven petroleum reserves by 20% -- was pummeling its stock price and angering shareholders. Regulators on two continents had started investigations.

So in early March the board acted, ousting Philip Watts, who had been managing director of the Anglo-Dutch company for almost seven years and chairman since 2001, and replacing him with Jeroen van der Veer, president of Shell's Dutch sister company, Royal Dutch Petroleum.

A quick cure for all those headaches?

Hardly.

... and so the company was forced to ask itself an unpleasant question: How many times can you fire your CEO in a year?