"WindowsUpdate_800F081F" "WindowsUpdate_dt000" Errors

Run  SFC /scannow in cmd

1. Updated the chipset drivers for Windows 7

2. Updated the all network driversfor Windows 7

removed the additional thing like  SATA hard drive in the second bay or USB any

This link will be help full to resolve the issue

http://support.microsoft.com/kb/2498452

http://technet.microsoft.com/en-us/library/ff817622(WS.10).aspx

Download and run the appropriate file:

Run system readiness tool and upload the checksur.log. Restart the computer and then install the updates

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=914FBC5B-1FBA-4BAE-A7C3-D2C47C6FCFFC

System Update Readiness Tool for Windows 7 for x64-based Systems

System Update Readiness Tool for Windows 7 for 32-Bit Editions