Need to reinstall Norton AV2009 from CD. What do I need to know before starting?

I had to format my hard drive and am putting things back together.  I was away from home, didn't have my Norton AV 2009 CD with me, so I temporarily downloaded a free AV program from the net.

I am at home again and want to reinstall my product.  I have the CD and the Product Key but do not have the subscription renewal number which was lost in an e-mail during "the problem".

What do I need to know, what do I need to do before reinstalling AV2009?  Are there questions or problems I am likely to encounter along the way?  What will I need to do once the reinstallation is done....update....other?

All comments and suggestions will be appreciated.

Thanks.