How do I load MS Office 2003/07 on my new computer?

I have just purchased a Dell laptop and am trying to load legally-purchased MS Office on it. I had to load 2003 before I could load 2007 (I had purchased 2003 during a time period that gave me the opportunity to get 2007 when it was released). After it loaded I was instructed to activate the program by going on line or by calling a phone number. If I don’t do either of these I have 49 more times to use the program before it shuts down. I haven’t tried yet because I already activated the program on my older computer. How can I activate it on the new one? Won’t they think I’m doing something illegal and block me?