Windows vista (KB973687)fail installation error code 80070020

Hi, am unable to install this update on my laptop. Have turned off all antivirus and real time scan software, tried to install in safemode and have even tried a cleanboot with no joy, am going mental pretty fast anybody any ideas please as i've none left
Thanks nuttymum

In that case i would suggest you to download fresh copy of Windows KB973687 and now try to update it once again and it had worked for me hope it works for you too and for error code 80070020 check out below link

http://forums.techarena.in/windows-update/708935.htm
http://forums.techarena.in/windows-update/710733.htm
http://forums.techarena.in/windows-update/1273974.htm