For error messages for installing SP1 on vista do the following
Following are steps for the same:
*Open run
*Type INF and open the file
*INF folder will open, look for AU.INF file (.INF file extension may not be visible)
*Right Click on AU.INF and Click Install
*It will ask for “wuapi.dll†file, click on Browse button
*Select the location as “C:\Windows\ServicePackFiles\i386†folder, click on “wuapi.dll†and then Click Open,
Click Ok and the service will be installed.
2 Start other required services
*open run
*Type the following commands and press Enter key after each one.
*net start bits
*net start cryptsvc
3. Re-register Windows Update ActiveX controls:
*Click on Start, and then Click Run
*Type the following file re-registering commands and press Enter key after every command
1) regsvr32 wuapi.dll
2) regsvr32 wuaueng.dll
3) regsvr32 wuaueng1.dll
4) regsvr32 wuauserv.dll
5) regsvr32 wucltui.dll
6) regsvr32 wups.dll
7) regsvr32 wuweb.dll
4. Rename the “SoftwareDistribution†and “CatRoot2†folders
Open command prompt with administrative privileges type the following
1) net stop bits
2) net stop wuauserv
3) net stop cryptsc
4) ren C:\windows\SoftwareDistribution SD1
5) ren C:\windows\system32\CatRoot2 CR2
****Restart the machine once****
Now once again in command prompt with administrative privileges type the following
1) net start bits
2) net start wuauserv
3) net start cryptsc
PS:Try to update now, if the commands do not work type all of them in upper case.