Windows Update Error 0x80070002 Generally means that there is a corrupt file in the windows update download cache. Easiest way to fix this is to simply stop the Windows Update service and then delete the entire windows update cache before attempting the Windows Update again.
Click START and type SERVICES
In SERVICES, scroll down until you see WINDOWS UPDATE
Right click on WINDOWS UPDATE and select STOP
Click START and type FILE EXPLORER
Go to C:\WINDOWS
Right click on SOFTWARE DISTRIBUTION, and select DELETE
yes, delete the entire SOFTWARE DISTRIBUTION folder
In SERVICES, Right click on WINDOWS UPDATE and select START
Try you Windows Update again.
If Windows Update still fails, try running the Windows Update Troubleshooter: