1) If you want to run eDrawings 2013/14 or newer on XP , simply copy the entire folder , e.g : eDrawings 2014 onto a flash drive , and run from there . Installation is not needed .
2) If you cannot set eDrawings as default or the exe parameter does not pass such that it does not register as an associate program ,
Go to Registry , HKEY_CLASSES_ROOT\Applications\EModelViewer.exe\shell\open\command , select the Data value to :
"C:\Program Files (x86)\Common Files\eDrawings20xx\EModelViewer.exe" "%1"
The underlined part , replaced with the directory as what you have installed ( newer version ) .