Loading up Vista

I had to reset my MacBook a while after using Vista, and with the Vista Disk inside it brings me to the install stage, without the disk it loads in Mac OS X.
How do I get it to start up in vista?

Hold down the option key while booting and you'll get a screen up where you can choose which OS to boot

Ok, thanks~
...options key... is that the one thats got alt on it or cmd?

It's the alt key

Thanks so much~

now I need some help with my external HD problem...