Hi, as of currently I am having a problem with my computer, now im not the best with computers, more of a small understanding, so please put up with me if i dont make sense

. My brother stopped using his computer, and has let me use it. I think some-time before he stopped using it he downloaded some sort of program that interupts the programs you are using... alot. The pop-ups that come tend to be more related to (You have a virus.. Buy this to get rid of it!.. System Alert!.. most coming from something called VirusProtectPro) They all look like something my bro would have originally gotten worried about and clicked on it to 'get rid of the virus' although i'v checked this computer out fully there is no virus.. but these pop-ups won't stop coming.. theres actually 2 little buttons on he bar right next to the clock/date tha say stuff like System Alert: Trojan... so on and if i click on them it takes me to an internet site.. also if my internet is off (wireless off basically) the buttons remain there and of coarse when i click on them it tries to take me to a site.. but cant) Now all these pop-ups minimize any current program i have running a few times in a row to deliver its message.. then i can click on what i was doing again (mostly gaming though which is when it gets really annoying) any tips or tidbits that could help get whatever is on my computer off would be greatly apreciated.
PS the 2 icons on my lower bar don't have a file/program name so i cant do a find command to search out the program.
Ty again

btw my normal pop-up blocker has no effect on these