Hey there,
I think you could try the following, in the following order, on the Firewall Settings:
1-Adjust security level to Complete Access.
if no internet..
2-Restore PF Default Settings.
if no internet..
3-Add Program Permision, Full Access, to your web browers and other programs that need Internet Connection
if no internet..
4-Open Ports and System Services to allow access to commonly used ports, such as 80/Http, for navigating on Internet.
finally..
5-Try Disabling Net Guard.
And then please comment in here if anything worked out for you.
Good luck,
Alex N.