Computer nto functioning properly...virus possibly?

Ever since I downloaded some software (don't remember what, think it was zango) I have been getting adware, which I hadn't received previously. Also on ie, sometimes when I click the new tab key, it ays connecting for about 1 second if not less and then goes away. Also, at ranom times, my mouse doesn't click properly (wireless mouse and lapto built-in mouse). Also, my computer sometimes freezes when I try opening microfost word or something like that. I have a vista comp. whe my computer messes up because of msword i clikc o it acouple of times and eventually, vista says options like restart, wait for program to respond, or close program. this has been happening very often. Please tell me the cause and a solution. Thanks