>what do you mean by recreate , everything work except when i try to build the application (.exe)

You can delete the .pjx file (and the .pjt if it exists, but is corrupt). Then create a new project - you can use the same name, and re-attach all your programs, forms, class libraries, graphics etc. Unless you have hundreds of files, it's usually not too horrible to do. Then you should be back to normal.