HELP !!!

here's the situation....

i bought microsoft office a year and a half ago and installed it on my computer. well, when the hard drive crashed last week, obviously the program was lost as well. the guy at the apple store told me i should have no problem re-installing office on my new hard drive.

i was skeptical, but the guy works at the "genius bar" at the apple store. who was i to say "yeah...doubtful." sooo i tried to reinstall it, but when i put the cd in the computer, nothing happens. it shows up, but it doesn't start downloading, nor does any kind of dialogue box pop up and ask me or tell me to do anything else. i really need Word to get things done for school, but i don't think i should have to buy it again, and plus the GENIUS told me i would've have to. so...please tell me. what are my options here? has anyone had this problem and re-installed office on a new hard drive? i also tried to just download a 60-day trial of office from the microsoft website to tide me over, but THAT didnt' work out either. ugh.

for now, i'm writing my paper on an online google doc. not a permanent solution.

HELP ME!!