All applications shows error message: invalid win32 application.

Hi experts,
I cannot open any applications in my computer. All seemed to be invalid Win 32 applications. I thought it was just a virus so I tried scanning it with Norton, but it is also an invalid Win 32 application. I tried system restore but unfortunately it isn’t also a valid win 32 application. All I have is to reformat my pc. But before that I would like the help of all experts without giving me the solution I have. Is there any way to fix this without having to reformat my computer?

C:WindowsSystem32rstrui.exe is not a valid Win32 application
C:Windowssystem32msconfig.exe is not a valid Win32 application
C:Windowssystem32FirewallSettings.exe is not a valid Win32 application
C:Program FilesNorton Security ScanEngine3.0.0.103Nss.exe is not a valid Win32 application
