I am not able to play on my office computer a video of ' .avi ' file shot
on my Canon A395 . I do get audio and our help desk at the office
checked all the settings but could not figure out. I can play other
video files from internet. I am able to play the both audio and video
on my home computer The same files can be played on other's computers
in my office. What settings do I need to correct so I can play video
part of the avi files and not only audio?

There are allways problems when you install codec packs in your
computer (ex SLD codec pack after nimo codec pack)
I suggest that everybody should use mplayer, has all codecs, but it is
not installing in windows system folder, only in program files  .
you can find it with a frontend for windows :
http://mpf.dzm.hu/

just use vlc.it will play anything