Rescue PC

Stop Pending or reboot Windows Updates
This is how would stop the Windows Update Service from installing pending updates.

sc stop wuauserv
sc config wuauserv start= disabled
c:
cd\windows\SoftwareDistribution
ren “Download” “Download_STOPPED”
takeown /f C:\Windows\winsxs\reboot.xml
takeown /f C:\Windows\winsxs\pending.xml
echo y|cacls C:\Windows\winsxs\reboot.xml /p everyone:f
echo y|cacls C:\Windows\winsxs\pending.xml /p everyone:f
del /q C:\Windows\winsxs\reboot.xml
del /q C:\Windows\winsxs\pending.xml
reg.exe delete "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired" /f
reg.exe delete "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer" /v InProgress /f

You may need to undo the disable or run the windows update fixer
Support.microsoft.com/en-gb/kb/2730071

Hope this helps
Cheers
Rescue PC