Ares how to get it off my computer?

My son downloaded this its some sort of music media but he said it didnt do anything so he tried to get it off. I was finally able to find parts of it when doing a search of all systems but when I try to delete it it says I need permission to do so. I run Vista and I gave my permission but the pop up keeps telling me I cant install without permission. How in the world do I get this crap off my computer? It is especially annoying because my firewall blocks it so everytime I go to any site including my browser the instalation window pops up saying it doesnt have the proper components to install and I have to cancel it everytime. Please help Im not exactly computer literate either.