Installer 3.1 v2: cannot find msiexec.exe file

This is really kicking my behind. The .exe file is missing from the system32
folder. I have attempted several suggested fixes, both from the windows
knowledgebase as well as other suggested remedies found performing web
searches. Nothing has worked. In the end, I can install installer 3.1, but
the .exe file is never there. As a result, I cannot install any software or
WIndows update which require its use. I am totally stuck.