(SOLVED) Unable to Run or Open Any Programs in Windows XP, Vista or 7

This happened to a lot of people already and is very annoying. When you open try to open your programs in your Windows computer, another program opens but then immediately produces an error message. To be specific, the file that you are trying to run are executable files with .exe file extension so when you double click to run the program, another and unknown program opens just to shoot an error message. Weird and annoying, isn’t it?

This happens when an executable file (.exe file extension) are being mistakenly associated with a certain program. This alters the registry that results to .exe files being opened by a particular program that only shoots an error.

The only way to fix this kind of problem is to reset the registry subkey for the file association of the .exe file back to the default setting. 

There are 2 possible scenarios for this. First, you are still able to open other programs like browsers, and you can open Explorer windows without any issues. The second scenario is the worst, when you cannot open anything on your computer by double clicking its icons.

Scenario 1: You are still able to run few programs

1. If this is your case, all you need to do is download the Registry Fix at the bottom of this article since you are still able to use your browser there.
2. After downloading the .REG file, double click on it to run it
3. When prompted to “merge” the registry keys, do an affirmative response (OK, YES or Continue)
4. Restart the computer and the problem will be resolved. 

Scenario 2: You are unable to run few programs at all

If this is your scenario, you need to follow few more steps since you need to create the REG file mentioned in Scenario 1 above since you are unable to download or run it by double clicking. Thus you need to  run it using Command Prompt.

1. To open the Task Manager, press CTRL + SHIFT + ESC.

2. Click File , press CTRL and click New Task (Run…) at the same time. A command prompt opens.
3. At the command prompt, type notepad, and then press ENTER.

4. Paste the following text into Notepad:

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. On the File menu, click Save as.

6. Select All Files in the Save as type list, and then type Exe.reg in the File name box.
7. Select Unicode in the Encoding list. Save it and remember the file location.

8. Return to the Command Prompt window, type REG IMPORT [filepath]Exe.reg, and then press ENTER.

9. Click Yes, and then click OK in response to the registry prompts.
10. Log off from your account. Then, log back onto your account.

You can then restart your computer and the problem should be fixed this time.