I tried uninstalling the application (in Windows Mobile 6.5, the "Remove Programs" option under All Settings, System) many times already. As to whether that procedure uninstalls the application "completely" as you instructed, I don't think it does because I should have been prompted to either Register or Use Trial, which I was when I first installed the application. Somehow some settings are still being retained and detected even after an uninstallation. After uninstalling and reinstalling, the messages font still is the same hard-to-read font, not the font that I had when I first installed the program. I am pretty sure that wiping all data on my device (return to factory settings) will remove IM+ completely from my device but that is not something I would want to do since it will also wipe all my other applications that I have worked on and devoted many hours to tweak.
I hope you find other solutions to my problem since this application is one of those that are indispensable to me. Thank you again for your reply.