In the list of services find:
stchost.exe (moto)
Rightclick that line and choose Properties.
On the General tab Stop and set the service to disabled.
In HijackThis click Config > Misc Tools > Delete an NT service
In the dialog box paste: moto
If that does not solve the problem with Windows Update can you check in Control Panel > Security Center > Automatic updates if it is set to ON
Regards,