As an extreme measure, delete everything except the absolutely needed files, which are the .lpi, .lpr, .lfm, .pas and any other file generated by you. Specifically, delete any auto-created resource-related file: project.lrs, project.res, etc.
Remember to backup first--even if just zipping the folder as backup--so as to be able to recover if you delete a little too much (hey, it happens...)