Just a note on blocking software. Gamblock is virtually impossible to uninstall unless you have very good coding / programmings skills and even then it can go horribly wrong and totally mess the system. Others I wont comment on. But gamblock is about as strong as it gets. Basicially when it is installed on your system ALL sites related to casinos/gambling are blocked including gaming forums and such like.
Nothing is ever 100% but it can give you another layer of cover and protection. But the real quitting starts from within. Self excluding from casinos is at the basic level and is a must in my book for any person who is struggling with an online based gambling addiction. But hey thats just me.