Check the link below for more context-setting. One possible solution to this dilemma: HP could try to hire Charles Phillips as its new CEO, at least providing a comparable level of insight into Oracle’s strategy and operations… but Oracle probably has a clear contract precluding that scenario.
The HP board should have been able to get an agreement that he wouldn't work for a competitor when they paid him off. As their lawsuit mentions use of confidential information and not breaking any agreement to work for a competitor, it's apparent that the settlement agreement with Mark Hurd didn't specify this. As it is, HP has launched a belated lawsuit which mentions the use of confidential HP information by Hurd as he carries out his new job.
Maybe a non-compete is often unenforceable in California law, but, even so, the amount of competitive information involved here would surely sway a court in HP's favour. This lack of a non-compete agreement looks like a blunder.