Cannot Boot From CD

I am trying to recover/reset my admin password on my laptop running on windows xp. I received the laptop from my university for being a full time student, but I no longer attend the school. I have burned an ISO image on a cd, and have pressed F10 on startup to boot from CD. After I hit F10 to boot from CD, a black screen appears with a blue box in the middle of the screen. The box reads “Administrator Password” with a key symbol next to it. I am guessing it is asking to type in the Adminstrator password, but I do not know it obviously, and when I hit enter it repeats the same phrase “Administrator Password” underneath the first and so on.. any ideas of how to get around this?