How to Get Windows Vista Service Pack 1

The Windows Vista SP1 Beta is now available but you won’t be able to get through Windows Update even if you click the ‘Check for New Updates’ button, I know I’ve tried it didn’t work. But by using a simple Registry Hack to make Windows Update download the necessary updates you may be able to get Windows Vista SP1 beta. Now remember the SP1 is still on beta form so you think twice in doing this hack. Proceed at your own risk.

If you still want to proceed here it is:
Open your notepad, Copy and paste these series of codes :
@echo off
reg add HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionWindowsUpdateVistaSp1 /v Beta1 /t REG_SZ /d a2c3c14a-9586-4d37-9aaa-79fbd64069d2 /f
reg add HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftWindowsCurrentVersionWindowsUpdateVistaSP1 /v Beta1 /t REG_SZ /d a2c3c14a-9586-4d37-9aaa-79fbd64069d2 /f
echo Vista SP1 registry key has been set. Please check for updates in Windows Update.
pause

Now Save this file as ‘SP1beta.cmd’ and save it anywhere you like. After saving the file, Run it…

If you’re UAC is Enabled - Right-Click on the file and select ‘Run as Administrator’
If you’re UAC is Disabled -Just Double-Click and run it like a normal Application.

Go to Windows Update

1. Click on the Start menu, on the Search Box type WINDOWS UPDATE, hit Enter
2. Click ‘Check for Updates’, and after a minute you should get a new update, KB935509. Install the update, and allow the computer to restart When it’s Done with the installation
3. After logging back in go to Windows Update again and and the new update should be update KB937287 but if it’s not there click on ‘Check for Updates’ yet again Install the update, and allow the computer to restart When it’s Done with the installation
4. After logging back in (for the third time) go to Windows Update again and and the new update should be update KB938371 but if it’s not there click on ‘Check for Updates’ yet again Install the update, and allow the computer to restart When it’s Done with the installation.
5. After logging back in (for the fourth time) the moment we’ve all been waiting for… go to Windows Update again and click on ‘Check for Updates’ and the new update should be Windows Vista Service Pack 1 Beta but if it’s not there click on ‘check for Updates yet again Install the update, and allow the computer to restart When it’s Done with the installation.
6. Finally Install the Update.. and your done

Source