For Windows7 SP1 32bithttp://www.microsoft.com/downloads/details.aspx?familyid=593a29c3-c459-4a39-9f25-016a5268fc7d
For Windows7 SP1 64bit http://www.microsoft.com/downloads/details.aspx?familyid=2d273f99-3460-4e84-9f2d-2a349bfc7ce6Instructions
1.To start the download, click the Download
button and then do one of the following, or select another language from Change Language and then click Change.
•Click Run to start the installation immediately.
•Click Save to copy the download to your computer for installation at a later time.
Also from M/soft Windows7 forum > >
Are you receiving any specific error messages?
In some other threads regarding issues with this particular update, the problem was fixed with one of two things.
First, I would suggest resetting your Windows Update Components. Please take a look at the article below with the Fixit to do this for you:http://support.microsoft.com/kb/971058
If that doesn't help, the issue could also be caused by a rootkit on your system.