Turn of auto-login for tv channel websites

I am unable to watch NBA on TNT on my studio PC because of the auto login feature. I have two accounts, one for the house which is cable, internet and phone and another account in my studio which is internet only. I want to watch the NBA on the TNT website in my studio but I can't login with my account that has tv because I'm being automatically signed in to my internet only, roommate account. Is there an option somewhere that allows me to turn the auto-login OFF?