How to Restore an Invalid Application in Win32

1. Ensure that the application you are trying to run is indeed a Win32 application. If it was designed for an older version of Windows (prior to Windows 95) or for DOS, it may not run properly on a 32-bit version of Windows. Similarly, if it was designed for a 64-bit version of Windows Vista or Windows 7, it definitely will not run. Check the source from which you obtained the program for further details about the application.
2. Uninstall the application that Windows is calling invalid. Then, download and install the application again, if possible. If you are downloading the program from the Internet, make sure the source website is reliable and that the file you are downloading actually is an executable program. If you installed the application from a CD, make sure the disc is clean and undamaged.
3. Scan the file with a virus scanner of your choosing, as it is possible that the application has been infected by a computer virus.
4. Boot Windows in Safe Mode and try to run the program there. Restart your computer and hold down the 'F8' key as it boots. When the Advanced Options or Startup menu appears, choose 'Safe Mode.' If the program runs successfully in Safe Mode, then some other application running in the background of the normal Windows boot is preventing it from executing. Reboot your computer and use your virus scanner to fully scan your hard drives, especially if you are experiencing this problem with more than one program. Also, use a free spyware/malware scanner like Malwarebytes Anti-Malware, which can be downloaded from the link in the Resources section of this article.