Computer help please

I throw in my restore cd in my cd drive and restart computer. It restarts and ask if I want to restore windows XP or 2)prompt CD. I choose #1 restore XP. It asks are your sure, yes. it then it says to presssy for yes n for n, I press y. I get this message CDR 101: Not reading drive R. I didn't know I had a drive R. What should I do.