How to Install Rundll32.exe

by Colette Larson

Rundll32.exe is critical to the functionality of your Windows operating system. This program file executes all of your dynamic link library (DLL) files and places their libraries into the system memory. Without this file, your computer will become unstable and run very slow. The file runs from your system directory, e.g., C:\Windows\System32. If it is running from another location, it has most likely been redirected or overtaken by a virus or Trojan Horse and needs to be reinstalled once the virus issue has been addressed.

Locate Copies of Rundll32.exe on Your System

Use the Windows Search tool to determine if rundll32.exe exists on your computer. Click on "Start," "Search," "All Files and Folders."

Type "rundll32.exe" in the "All or Part of the File Name" section.

Select "All Local Hard Drives" from the "Look in:" drop-down list for the best results and click "Search."

Make note of any specific paths where the file is located.

Delete any occurrences of the file that are not in C:\Windows\Options\Install, C:\ServicePackFiles, or the cabinet files from your initial Windows Installation. These are indicative of a virus or Trojan Horse that need to be addressed separately.

Continue to "With a Copy of Rundll32.exe on Your System" if you have located a legitimate file copy. Skip to "Without a Copy of Rundll32.exe on Your System" if you have not.

With a Copy of Rundll32.exe on Your System

Click "Start," then "Run", to open the command window.

Type "msconfig" in the field labeled "Open" and press "Enter." This opens the System Configuration Utility. Click the "Expand File" button on the General tab.

Type "rundll32.exe" in the "File to restore" field. Type the location of the file copy in the "Restore from" field, e.g., "C:\Windows\Options\Install". Type the location where the file should be located in the "Save file in" field, e.g., "C:\Windows\System32".

Click on "Expand." If the file is located and copies into the System32 folder, your system file has been restored. If the file cannot be reinstalled from the alternate location, you will need to reinstall Windows to recover the file.

Without a Copy of Rundll32.exe on Your System

Insert your Installation Disk into the CD drive.

Click "Start," "Run" to open the command window. Type "msconfig" in the field labeled "Open" and press "Enter." This opens the System Configuration Utility. Click the "Expand File" button on the General tab.

Type "rundll32.exe" in the "File to restore" field. Type the drive location of the installation disk in the "Restore from" field, e.g., "D:\". Type the location where the file should be located in the "Save file in" field, e.g., "C:\Windows\System32".

Click on "Expand." If the file is located and copies into the System32 folder, your system file has been restored. If the file cannot be located individually on the installation disk, you will need to reinstall Windows to recover the file.

Warning

  • The Rundll32.exe process is registered as a backdoor vulnerability that may be used by hackers to distribute malware. These security risks need to be removed from your computer with a reputable anti-virus software.

About the Author

Colette Larson is a freelance writer, Web designer and Web traffic strategist from Florida's Gulf Coast. As a Michigan State University graduate, Larson built a successful career in corporate information systems over 25 years, beginning as a help desk technician and working her way up to project management.

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