I’ve been asked to fix a computer that seemed to have a lot virusses. One rootkit preventing internet access to the Windows Update server. I fixed this using TDSSKILLER

After this I could at least visit http://update.microsoft.com but received a 0x8024D007 error.
To fix this:

1) Open the registry (start/run/regedit) and browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\wuauserv

2) Right click wuauserv in the left pane and select “Permissions” make sure you have:

– System at FULL CONTROL
– Administrators at FULL CONTROL

(if you mis these entries you can add them using the add button).

3) Now using the same registy editor browse to:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Svchost

4) Right click Svchost in the left pane and select “Permissions” make sure you have:

– System at FULL CONTROL
– Administrators at FULL CONTROL

Close the registry editor

5) Download the latest Windows Update Client using this link
Leave me a quick reply if it helped you, good luck!