Windows Installer won't install Open Office and Apple Software Updates for...

[fardin]

...Safari, Quicktime and iTunes...... and also Version Tracker Pro. Other softwares install without any problems like Advanced Windows Care, Total Uninstall, FileMenuTools. I can't use the Windows Installer Cleanup Utility package which I downloaded from the Microsoft website.... The Windows Installer service is also missing in 'services.msc'. I have tried to reregister it by typing 'msiexec / unreg', pressed ENTER, typed 'msiexec / regserver' and pressed ENTER ... but the problem remains unresolved. It is still missing in the services. ..... I am using Windows XP Home, SP2. By the way six of the latest windows updates also could not install. Whenever I turn off the computer, the updates installation prompt is always in the 'Log Out,Turn Off and Restart' window but they don't get installed. .. How to overcome this problem?