so my nana has had a computer now for about 10 years (shes in her 80's)

lately ive noticed whenever i go over there she complains that her homepage has changed and last time there was even a toolbar on her google chrome.

its coming from the games she downloads, she doesn't untick the 'please change my home page and default search providers to *insert awful search provider here*' boxes and ends up with a computer full of adware and spyware.

what i want to know is if there's a way to permanently stop third party programs from changing her settings and installing toolbars and browser addons without making her account a limited one as she likes to play games and download new games, i cant be there to install them for her all the time either.

it never used to be this bad, i think recently lots of 'free' software has been including all these tricky extras during installation and if you don't read it very very carefully they install other little bits that no one wants. Sometimes dispite even my best efforts they manage to install.

any ideas?