If you come across any issue in installing a software or updates in Windows Vista check if the installer file is there,
If no then download the file name "MSISERVER"
Unable to Access the Windows Installer
Updates failed to install
Extract the file, open “REGEDIT” and then import the registry file
Restart the computer.
Open ‘’Services.msc’’ and then change the startup type to automatic and then start the service, Once done
Try installing the Updates or the software that was not working.
Note : System Restore might give you a temporary fix