Community Tip - Your Friends List is a way to easily have access to the community members that you interact with the most! X
You could try to download the installation source provided through Vladimir's link(s) here:
(Of course after wiping all mathcad 14 related stuff hanging on your computer first.)
Also make sure that you have (pre-)installed the right prerequisites. Mathcad is quite picky about the correct version (no sooner, no later) of MSXML.
Success!
Luc