Lost my Office 2007

*Sigh*...where do I start?

Yesterday, I was downloading the SP1 for Vista when my laptop froze (Acer Aspire 4315). After waiting a while to see if it would right itself, it didn't, so after about 15 minutes, I manually shut it down and on starting it back up, I saw the Acer screen and Windows was searching for a solution to the problem...it was only after a couple minutes, it dawned on me that my laptop had crashed (it has never happened to me before, even with my sometimes lame but oh-so-reliable desktop). On my mother's advice, I let it shut down and left it for a while, in the hope that it was an error, but on start-up again, I encountered the same problem. Instead of stressing, I decided to tackle the problem later on which I'm doing now. I went on the Acer website and found an eRecovery solution, and after trying it, my laptop seemed to right itself (half an hour in the process) but hey, I was just so happy I was back on that I'll be grateful for small mercies. Anyway, now that's it's up and running again, I was going through my system and lo and behold, NO MORE OFFICE 2007. Can someone help me please? I have no idea where it went and what to do. Of course, easy solution would be to reinstall it from a CD, right? But if it's already there, I don't want to put it on again. If I do a system restore to locate it, what's gonna happen? I'm not tech savvy, but please help.