1. Open command prompt:
1) Click Start, and then type cmd in the Start Search box.
2) In the search results list, right-click Command Prompt, and then click Run as Administrator.
3) When you are prompted by User Account Control, click Continue.
2. At the command prompt, type "net stop WuAuServ" (without quotations) and press Enter.
3. Click Start, type "%windir%" (without quotations) in the Start Search box and press Enter.
4. In the opened folder, look for the folder named "SoftwareDistribution" and open it.
5. Double
click the DataStore folder and locate the DataStore.edb file.
Delete it.
Thats all !
Note: Windows Update history is in a file and if you would like to delete it,
all the update history, not just the installation failures will be
removed.