Recurring virus?

I have a problem with a virus - I guess.

When I enter a term on google, I get a list of options and when I click on one, I don't go to that site put to some other site not at all related to what I'm looking for. If I try to "go back" that site just comes up again. If I try to enter the url of the site I googled, I still can't get to it.

Last night I scanned everything with Norton and it was fixed, but this morning I have the same probem again. What else can I do?