I have several keynote presentations on my computer but now am getting the message that the program cannot be installed "because of a problem." All this started when I bought microsoft office for  University (2011). What is the problem and

I have several keynote presentations on my newish computer but am not unable to open them. I get the message "keynote cannot be installed because of a problem" (unspecified). Does anybody know why this happend? Does it related to using Microsoft "University"  2011? How can I fix it? Thanks!

Thank you for your reply.
I just tried the 3-step process suggested on http://support.microsoft.com/kb/2431353
This all started when my mouse/thumb clicker was going crazy. Found an expanded battery. Obviously need a new battery. Unfortunately must wait 6 weeks to get my new battery. Meanwhile, I'm running my computer on AC only, as there appears to be no other option. I was informed that when using AC only (no battery) some high-energy-use programs like Office might not function.
Do you know if there is away to use office even when just using AC and not having the battery in? I'm doubting if I have other OSX problems because everything else works: email, safari, itunes, iphoto, quicktime, etc . . . . ?