Want to install 3rd OS, but can't boot from CD?

I have a WD 250g hard drive that I have split into three partitions. One is for Vista, one for XP, and a third I kept blank. I want to install Ubuntu onto the third partitions so I popped in the disc and restarted and hit boot from CD and nothing happened :rage:. I get a screen that says "boot from CD:" then it goes straight to the OS choice screen and I don't get another option. I've tried nearly everything I can think of to get this to work and no dice. I have set every boot option in my BIOS to boot from CD and it STILL boots from the HD. I used EasyBCD 1.7.1 when I first installed XP and Vista and I think thats what is throwing me the curve balls. Is there a way to boot from CD that I'm just not finding? If not, is there a way to completely remove EasyBCD from my system so I can install OSL2000 which I know works? Please help:x
Welcome to NST Tacotanker,
EasyBCD is just a user-friendly editor for the Vista BCD.
Vista is in charge of your boot, EasyBCD isn't doing anything on your system if you're not actually executing it to make some BCD changes. Uninstalling it won't do anything except make it unavailable next time you need to use it.
I can't give you specific Ubuntu advice (not a linux user myself), but there is a wiki guide
and if you check back later, one of our experienced linux users will advise you if the wiki doesn't answer your questions.
Have you verified that your BIOS boot order is correct (optical before HDD) by booting your Vista DVD or your XP CD. (Don't do anything obviously, but just to check that it's the specific Ubuntu CD that's causing the problem, not your CD drive)
Did you burn the ISO correctly?

Do not burn it as data (but as an image) and at the slowest speed your burner goes.