Clean Up Computer

A program known as "Win Fixer" recently installed itself to my computer. Iv dealt with this program before, on another computer, its spywear that hides itself and creates more and more popups that appear the moment i start up an internet explorer or Fire fox copy. Iv deleted anything named "Win fix" that the search function on windows explorer found, but the popups continue dispite my virus scanner saying I have no spywear on the system. Its gotten even worse now. If i open any internet program windows says it has to close windows explorer! Then my startbar disapears, my computer lags for a few moments, and it appears again, but if i dont close the internet explorer or fire fox it dose it again within a few moments, and dosnt stop untill the internet is closed. I dont want to buy ANOTHER anti spywear program and im not good enough to change anything inside windows itself. Is there any way short of erasing my hard drive to fix this?