How to turn on/off boot messages when Ubuntu starts?

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http://askubuntu.com – Is there a way to easily turn on/off showing the boot messages (loading the services) when Ubuntu starts? My machine uses WUBI for boot-up. The reason I am asking is to figure out if the reason for the lockups is caused by events which happen a boot-up. I see messages which are cleared out before I can read them. If there is a place where all errors are logged, even when the booting file system is read, I would like to know so I can read them instead. (HowTos)