I am using OE (V#4.72.3110.0) and am unable to designate OE as my default e-mail program through Tools/Options. I check the box, click on Apply and when I return to Tools/Options the box is again unchecked.
In IE (V#4.72.3612.1713) I am not offered OE as an option under Internet Options/Programs. Only Windows Messaging is offered.
NOTES - I have properly un-installed and re-installed OE twice. Neither time did this solve the problem. Both times, when I first tried to open OE it hung up and had to be closed down with Alt-Ctrl-Del. Then I was able to open, but the original problem still exists.