Search and replace text in XML file?

[todd.tabern at gmail.com]

I'm looking to search an entire XML file for specific text and replace that text, while maintaining the structure of the XML file. The text occurs within multiple nodes throughout the file.
I basically need to replace every occurrence C:\Program Files with C:\Program Files (x86), regardless of location. For example, that text appears within: 
<URL>C:\Program Files\\Map Data\Road_Centerlines.shp</URL>
and also within: 
<RoutingIndexPathName>C:\Program Files\Templates\RoadNetwork.rtx</RoutingIndexPathName>
...among others.
I've tried some non-python methods and they all ruined the XML structure. I've been Google searching all day and can only seem to find solutions that look for a specific node and replace the whole string between the tags. 
I've been looking at using minidom to achieve this but I just can't seem to figure out the right method.
My end goal, once I have working code, is to compile an exe that can work on machines without python, allowing a user can click in order to perform the XML modification.
Thanks in advance.