Fake Anti-Virus Pop-Ups

My PC (DELL desktop) suddenly has bogus pop ups for viruses, and of course a tool to remove them. This tool, "Spyware Protect 2009", installed itself onto the taskbar, and cannot be removed. It is NOT shown in add/remove programs Accessing some web sites instead just displays a page that I need to use this tool to protect the pc. At other times, pop up warnings come up sporatically tellme of an alert, and to buy the tool (its a demo it says). I just want to remove it, how do I start to do that? thx.

ketchlv