I deal with this every day.
Netster is one of many "home page hijackers". What they do is change you home page (usually to a page that looks like a search engine but is really an advertisement site where all the links go through that companies servers).
They also will make changes in the registry so that if you try to type in a URL without the "http://" (like just typing in "
www.taldren.com") redirects to thier page then redirects you (supposedly) to the site you requested. The problem is, they rarely work.
The temporary work around is to type all URL's completely, using "http://" and so forth. Then, get Ad-Aware from
http://www.lavasoftusa.com and do a smart system scan, then remove everything it finds (and it will find a lot of stuff, I guarantee it).
If that does not get rid of the hijacker, you may be looking at doing some registry hacking.
Once it's gone, though, educate your grandmother about these things. Do not click just any install button you see. If you get a window that looks like a windows dialog box with an Ok and Cancel button, but it's in an IE window, DO NOT CLICK ANYWHERE IN THE WINDOW. Instead, close the window with the big red x in the upper right (assuming she's running XP), doing otherwise will install malware on your computer. In fact, do that with all popup windows, at least until you can get a pop-up blocker installed.