I own a laptop that is around two years old, its a Toshiba Satellite L300, with Vista Home Premium as operating system.
I first noticed this problem when attempting to reinstall IE8. [Please don't start an 'IE9 is better' discussion.] It was having bugs, so I tried to uninstall it. No luck. I was told to install IE9 because it automatically uninstalls previous IE versions, so I did, and went to Programs And Features, and then to the Updates page where I was supposed to be able to uninstall it. It wasn't there.
I proceeded to try the Cmd program and uninstall it that way. It repeatedly asked me for administrator permission. It has to be noted - I am an administrator - but nothing happened. My account is the second, my Dad has the 'Admin' account that is the first account Vista makes. However, even on that account it would not uninstall.
It is also impossible to install Chrome or Firefox.
This may have something to do with an update that I have several times tried to have it install, but it wouldn't.