i think i may have a virus or something, none of the top letters on my keyboard work when pressing the shift key.

i've ran updated versions of, cswshredder, microsoft anti-spyware, microsoft trojan remover tool & spybot. Finally i've ran no-adware which has picked up 51 items only it wants me to pay $37 to remove them.

whan can i download free to clean my computer of this shit?