800F081F error when downloading sp2 on vista

hi! can anyone help me how to fix this error 800F081F .everytime i try to download this updates it keeps stopping on 41 mb 21%.the updates is 35mb-344mb..i tried to scan all the error on my pc thru regcure and it fix everything,but still i cant download this updates...Thanks in advance!!!!
i just checked my updates history now and i found out that there are some updates for my sp1 that failed to install how can install those updates that failed,cause when iam checking updates now only sp2 is available.

Hello Mykel, welcome to the forum.

Before going for any further update, please make sure that you have logged in Windows with the administrator account and the computer could access Internet connection properly, which will provide you enough privilege to install Microsoft Update.

Disable any anti-virus/spyware application or firewall on the computer during installation.

Moreover, the given below below link may help you fixing your problem:

Windows Vista SP2 Won’t Install: Fixes

Thanks.
Arvin

tnx for the reply..but i did everything in the link you gave me but the problem is still there.i tried the standalone download and it keeps giving me this error 800F081F. i tried to download the kb955430 cause it says this update is needed for future apdates,but the update doesn't apply to your system...i've read a lot of forum but can't find any solution yet..