HHHEEEELLLPPP!!!! i think im keylogged!!!?

i downloaded a file and my norton firewall thing told me there were a couple of attacks but it protected them but i think i have the key-logger file right here but when i try to delete it it says we need permition i say yes but it pops back up i am the admin of this computer plzplzplzpzlpz help my runescape account is in trouble !!!!=D