thats what i did
Use the installer for the program, not the add/remove programs in your control panel. Lockheed Martin states this specifically in their forums.
Same here Adam! I uninstalled using an advanced uninstaller I purchased that uninstalls, then scans for any leftover files and deletes those also. Plus I went directory by directory deleting leftover folders where necessary and then a final scan to be sure everything was gone. Installation of 2.5 went as advertised after that. By the way, I did save all the important files from the folders in question first as well as all freeware aircraft, gauges, effects and so on.Ooops. Didn't know this. I uninstalled V2.4 via the control panel un-install panel and all went fine. Install of V2.5 went smoothly.
If it was me I'd email LM with your order info so they can reset your account and then remove the program manually (assuming you haven't found the usual uninstall route).
Adam