VIRUS/CLEANER REMOVAL HELP NEEDED?

I accidentally downloaded the 'MS Removal tool' and now i can't get rid of it. It wont allow me access to my other cleaners like CCleaner and my IObit Toolbox and has prevented me from accessing my Google browser, and anything where i could get rid of it. And will NOT let me uninstall it. The NAG Screen is driving me nuts...anybody know a way to GET RID OF IT FOR GOOD or a cleaner that WILL work under these conditions? I can't access anything but FireFox and that's iffy.