Fixed! I ran the XP repair procedure. Ran the driver test, rebooted, and fired up Mach3. The screen did not load... Was a white screen with just the main file menus. I replaced my .xml fie and custom screen files, reinstalled flash (I got an odd error while rebooting the first time after the XP repair) and rebooted. Restarted Mach and its running like a champ again. In fact it loads really fast now. No problem loading files now.
Thanks for the help and suggestions!