Run an .msi Installer File as Administrator

An example to trying install application ".Net Pet Shop 4.0 on Windows Vista" that no right click option and must Run as administrator for .msi files. You can, however, run the CMD prompt as Admin, then the following:

msiexec /a "Microsoft .NET Pet Shop 4.0.msi"

Another useful command to crack open a .msi installer file:

msiexec /a "Microsoft .NET Pet Shop 4.0.msi" /qb TARGETDIR=c:\temp

It might also help to do a:
runas /user:domain\user msiexec /a "Microsoft .NET Pet Shop 4.0.msi"

Other easier method is run cmd.exe as administrator and then launch .msi file