How to fix if Default Program of .exe files in Windows is changed?

If you change the default program of the executable files in windows you cannot open any .exe files directly.But you can open it by Right click on an executable file->Open with->Choose default program->Uncheck the always this program->Browse->And select the program you want to run ->OK.And to fix the problem just delete the value in the registry HKEY_CURRENT_USER/Software/Microsoft/Windows/Current Version/Explorer/FileExt/.exe/Userchoice.But I don't know if the Windows Registry Editor can be opened this time. The Windows Registry Editor is located at C:\Windows.It's easy if you have installed some other registry editors try to open it by the method I said above.