What the Heck is This Trash?

A while ago I tried downloading this download accelerator for Kazaa (produced by the Kazaa company itself of course). I didn't like it so I took it off but it put all these browser tool bars programs and a bunch of other useless junk programs onto my computer. The problem is I can't delete them. When I try to remove them with the Wizard, nothing happens and when I try to delete them manually, it tells me access is denied. HOW COULD I BE DENIED ACCESS TO STUFF ON MY OWN COMPUTER!! >:(
These things also run in the background and eat up ram, so I have to turn them off manually. My question is, how do I get rid of these things without doing a complete erase of my hard drive?
These things also run in the background and eat up ram, so I have to turn them off manually. My question is, how do I get rid of these things without doing a complete erase of my hard drive?