How to fix .exe file association in Windows? [duplicate]

You can fix it by taking a look at this Microsoft page: KB950505.

There is a "Fix it for me" program linked from the page. Alternatively, you can manually follow these directions:

Because you cannot open .exe files normally (this also happens with certain viral infections), you have to use a roundabout way to make the necessary changes.

1. Open Task Manager (CTRL-ALT-DEL)

2. Press and hold CTRL and click File - New Task (Run...). This will open a Command window.

3. Type "notepad" and press Enter. This will open Notepad.

4. Paste the following text into the Notepad window:

   Windows Registry Editor Version 5.00
   [-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.exe]
   [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.exe]
   [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.exe\OpenWithList]
   [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.exe\OpenWithProgids] "exefile"=hex(0):

5. Click File - Save As.... Set the file type to All Files, name the file "fix.reg", and set Encoding to "Unicode". Remember where you've saved it.

6. In the command window, navigate to where you saved fix.reg and type "reg import fix.reg"

7. Click Yes and OK to any prompts.

8. Reboot your computer.

Note: I had issues pasting the specified text for the registry import. If the above text doesn't work, go to the KB article linked above and paste from there.