Any Ideas on unblocking all blocked internet access?

My sister called me and told me she had accidentally blocked internet access on her computer. When she went to connect, a little thing popped up saying a program was trying to access her computer and she clicked the 'do not allow' button and made it permanent accidentally. She now can't access the internet at all. We've tried resetting the settings, plugging and unplugging the cables, restarting the computer and looking around the internet properties window *changing the home page and all*, but she still can't get online at all. Anyone know how to unblock the entire internet?
Any Ideas on unblocking all blocked internet access?
It is firewall related, either Windows or another 3rd party program. The setting you want is within that program. I am pretty familiar with most firewalls so if you want go ahead and shoot me an email and I can help further.