Error in disabling Microsoft Office version 2007

I have owned a disk program of Microsoft office enterprise of 2007 which is an original one. I used it when the trial version of Microsoft office 2007 came to the point of de-activation. This is installed already since I bought this net book of Asus Ee PC and now I wanted to uninstall it. Midway in installing it I encountered an error: A required file is corrupted or not available and it can't proceed. From its original source, set-up should be run again. OK. So I click the Ok option and it stops installing.
Please help. I need to uninstall this one prior I can install the usable one. And since I don't know the means of error I don't know what to do next.
