If I click a desktop shortcut (not a bookmark) to any about:"page" (i.e. about:config), the shortcut opens Internet Explorer and brings me to the Internet Explorer "Navigation to the webpage was canceled" page.

A bookmark does work while in the bookmark manager, It also works if I drag n drop from desktop to browser, but if I try to use it from my desktop, it does opens IE..

Because at one point in time it all worked the way it is supposed to, I am guessing that it happened when I was fiddling with uninstalling Firefox.exe and replacing it with Firefox portable.

Probably due to being over aggressive with the use of Revouninstaller, I messed up something in the registry by deleting something that doesn't GET corrected even when you use the Firefox installer.

Anyway, that's my theory.

There is no "open with" on any of my XP shortcut context menus.

I did a registry search, and these were the only about: related things that came up.

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main]
"Extensions Off Page"="about:NoAdd-ons"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main]
"Security Risk Page"="about:SecurityRisk"

thanksCheck and make sure Firefox is set as the default browser...
It's either that...or you're infected.
Run scans with all your protection apps after doing the above.Firefox is my default browser.  I have been searching for a solution for a while now, and have TRIED all the conventional remedies that I could find.  I am not infected.  Everything else systemwise operates fine.

All "REGULAR" internet shortcuts and bookmarks work normally.   

The only ones that don't work LIKE the others are the ones with the about: protocol.

The reason I believe it should work is that I think (operative word think, but with some confidence) I remember a time in the past when it did. 

Can anyone say definitively whether or not by default Firefox is designed to open this type of shortcut (to about:home, for example) in Firefox?