Connection problems

I'm having issues connecting to the client and/or to games sometimes, and I'm hoping someone has had a similar experience.

I'm getting the generic 'Unable to connect to the PVP.net server' message and that it thinks I'm being blocked by a firewall - it leads me here: https://support.leagueoflegends.com/entries/234161-connection-failure-error-when-logging-in

I've done everything it has recommended, excluding syncing the windows clock because I get a message that 'System error 5 has occurred. Access is denied' which is also kind of weird.

I was playing fine earlier from the same connection, but for some reason I failed upon logging in and am now getting these messages. I use a Verizon FIOS connection with the firewall settings on Low (can't turn this off to my knowledge). I disabled the Windows Firewall and AVG antivirus. I created the following rules in the port forwarding section in my router: UDP 5000-5500 TCP 8393-8400 TCP/UDP 2099 I also ran the latest windows update, but still I can't connect to the client.

Does anyone else have any recommendations?