If you are running windows 7 you can now down load service pack 1 updates.
Windows 7 and Windows Server 2008 R2 SP1 helps keep your PCs and servers on the latest support level. It also provides ongoing improvements to the Windows Operating System (OS), by including previous updates delivered over Windows Update as well as continuing incremental updates to the Windows 7 and Windows Server 2008 R2 platforms based on customer and partner feedback. This enables organizations to deploy a single set of updates.
If you want to download Windows 7SP1 to use off line click here.
However if you only have 1 PC to update use the normal automatic windows update instructions here.