Change your boot order so you arent always trying to boot off your DVD drive, that is the simpliest way.
I would leave it on all errors except keyboard because for the most part if there is an error during POST its usually pretty significant.
I did all of that and it seemed to fix the problem (of the boot process hanging before going to the boot loader). However, first rarely but now every time, the boot process hangs after "Verifying DMI Pool Data". It then used to not hang after a restart (via the power button) but lately it takes 3-4 attempts of booting before it goes through.
I have the latest BIOS and the latest drivers - what else can I do to find the cause of this, or to fix it?