How to Reinstall Wuaueng DLL
A Dynamic Link Library, or DLL, file is a piece of programming code that Windows and other programs can borrow to run a specific function. It's much easier to design a program to be compatible with DLL files than to include the same code for the same function in each piece of software. In addition, DLL-compatible applications take less space on the hard drive. Wuaueng.dll is part of the Windows update service. If this file is missing, the Windows updater might not run correctly. Fortunately, you can download and reinstall the DLL at no charge.
Download a free copy of the wuaueng.dll file (see Resources.)
Right-click the downloaded wuaueng.dll file and click "Copy." Click the "Start" menu and select "My Computer." Double-click the "C:" drive, open the "Windows" folder, open the the "System32" folder, right-click anywhere in a blank space and select "Paste."
Click the "Start" menu, type "Run" into the search box and click "OK." Type "Regsvr32 C:\Windows\System32\wuaueng.dll" into the "Run" box and click "OK" to register the DLL. Click "Yes" in the pop-up to confirm the registration.
Restart your computer.