iexplore.exe virus/trojan

i currently have some sort of trojan/virus/malware running on my computer currently.

 

something attacked my computer and norton claimed it stopped it but all of a sudden i started having internet explorer open up with ads. i don't use IE anymore so this was a surprise. when i open the task manager i see multiple copies of iexplore.exe running, and sometimes i get sounds from ads that they are running on sites that i can't see. i feel like i'm playing unwinnable game of whack-a-mole.

 

any suggestions?

 

i've been told i might just want to reformat my hard drive. if i do that will i have to repurchase my norton internet security as i've installed my other allowed installations on the rest of the computers in the house?