I need a FREEware anti-spyware/adware program... suggestions?

I need a spyware/adware scanner/removal program. I've tried SuperAntiSpyware and am not satisfied with it. I've tried the following that would not install on my computer: StopZilla, Spyware Doctor, and SpyBot. Also AVG, AntiSpyware 2009, and XoftSpy are not free, but trial versions which I do not want. I've seriously tried about 7 programs listed in responses to similar YA questions...