Vista - SP1 update error code 0x8007002

I am a newbie silver surfer to computers and have never been able to update to SP1 since it came out due to the above error code. I have vista home premium 32 bit on my laptop which was pre-installed when I first bought it in 2007 - I have tried to install it various times but with no success - even trying to download SP1 as a 'stand alone' install from download.com or vnunet - nothing seems to work - it downloads about 20% of it but I then get the error code again - and have never been able to figure out why, even 'googling' the error code to try and find an answer.... can anyone help?

Try below tool to fix this problem Description of the System Update Readiness Tool for Windows Vista and for Windows Server 2008

Thank you Flavious for your help,
I downloaded the readiness tool and waited for something to happen like a report back or something - does it do that? or do I just try and download SP1 again?

Yes

ps the error code mentions 'file not found' - what kind of file is it looking for?

Just install "stand alone" version of SP not from WU

Thank you again for the info above Flavius (apologies for spelling your user name wrong also - slip of the keys!), but by the time I received your info above, via email, I had already downloaded/installed from WU as the 'readiness tool' had obviously fixed whatever was wrong before....everything seems to be running fine on my laptop since the SP1 download, and no problems so far with anything... what would have been the difference if I had used the 'stand alone' install and not Windows Update?

Practically no difference.
SP X (X-number) from WU included only hotfixes never appeared before in WU or Microsoft Download Center until available only for special whish,given only for Microsoft Support for individual users which had non-documentary trouble +new improvements
SP X (X -number) includes all hotfixes (published and non-published) which appeared since last SP + improvements - of course SP1 from Microsoft Download Center included all hotfixes which appeared since Vista debut.
Things to know before you download Windows Vista SP1