You cannot open files that have extensions such as .exe, .com, and .lnk on a Windows XP-based computer (923077)


The information in this article applies to:

  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition
Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

SYMPTOMS

When you try to open files that have extensions such as .exe, .com, and .lnk on a Microsoft Windows XP-based computer, you cannot open the files. Alternatively, the Open With dialog box appears.

This problem occurs even if the following conditions are true:
  • The computer is in safe mode.
  • The extensions have default registry entries.

CAUSE

This problem occurs when one ore more of the following conditions are true:
  • The registry values that are associated with the file name extension are corrupted or the values are missing.
  • The computer is infected with a virus.

RESOLUTION

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this problem, follow these steps:
  1. Restart the problem computer in safe mode, and then back up the registry.
  2. Click Start, click Run, type command /c copy %Windir%\regedit.exe regedit.com, and then click OK.
  3. Click Start, click Run, type regedit, and then click OK.
  4. In Registry Editor, compare the following registry subkeys with the registry subkeys of a working computer for the file name extensions that do not open:
    • HKEY_CLASSES_ROOT\.<file_name_extension>
    • HKEY_CLASSES_ROOT\<file_name_extension>file
    • HKEY_CLASSES_ROOT\.<file_name_extension>\<Sub_Folder>
    If you cannot open the .com files, compare the following registry subkeys with the registry subkeys of the working computer:
    • HKEY_CLASSES_ROOT\.com
    • HKEY_CLASSES_ROOT\comfile
    • HKEY_CLASSES_ROOT\.com\PersistantHandler
  5. If you find any difference between the registry entries on the problem computer and on the working computer, restore the default values of the corrupted entries. To do this, follow these steps:
    1. Select the registry entry that you want to change.
    2. On the Edit menu, click Modify.
    3. In the Edit String dialog box, type the value that you find on the working computer in the Value data text box, and then click OK.
If the problem persists, follow these steps:
  1. Note the CLSID number that is found in the HKEY_CLASSES_ROOT\.com\PersistantHandler registry subkey.

    Note The CLSID consists of a long set of numbers that is enclosed in braces ({ }).
  2. Compare the CLSIDs with the CLSID that is located in the HKEY_CLASSES_ROOT\CLSID\<CLSID_number> registry subkey. If these CLSIDs differ, restore the default values of the corrupted entries.

MORE INFORMATION

Consider the following scenario. You cannot open files that have a .com extension after you install third-party software. In this scenario, the registry of the computer is updated with the following registry subkeys to resolve this problem:
  • HKEY_CLASSES_ROOT\.com
  • HKEY_CLASSES_ROOT\comfile
  • HKEY_CLASSES_ROOT\CLSID \ {098f2470-bae0-11cd-b579-08002b30bfeb}
Modification Type:MajorLast Reviewed:8/24/2006
Keywords:kbtshoot kbprb KB923077 kbAudEndUser
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