Ubuntu disk won't boot now that I have Mint installed

[kilikman]

Please help, I have used Ubuntu in the past and I dug out an old laptop, I couldn't find my Ubuntu 9.04 disk so I just put Mint in, this laptop was using XP so I was able to use the boot from CD helper, however I have found my disk and now want to switch back however this laptop won't let me boot from this or any other disk (Windows included), this is starting to get VERY annoying as I can't run the CD helper on Linux either, help would be massively appreciated!

[mrgnash]

Check your bios settings; is your machine still set to check the optical drive for bootable media before checking the hard drive?

[kilikman]

I can't get into the BIOS menu as I have forgotten my password, is there any CD boot helpers for Linux at all?

[mrgnash]

I am not familiar with the concept of a "CD boot helper", but if you have forgotten your BIOS password, you may need to manually reset your BIOS (http://www.wikihow.com/Reset-Your-BIOS).

[kilikman]

Well I would rather not disassemble this laptop as it is property of the school I go to, as for one of the methods I can't do that as it asks for the password the moment I enter the BIOS screen.