I'm not sure if you guys will be able to help me, but it's worth a shot since nobody is interested in my topic on the Tech Support Forum in League of Legends.
I've got a very annoying problem: whenever the LoL client is running on my PC, I'm unable to browse web pages in Firefox/Internet Explorer etc. (web pages sometimes load after around 5min, even google). It actually happens when I'm not in a match, but in the main client. It's some kind of a simplified web browser without an address bar (there's just buttons like Shop etc.). In a match it all works fine. In addition the shop and chat pages take ages to load.
Sorry to hear that. anyway, looking at your case and mine, i still suspect a conflict between the lol launcher and certain antivirus programs. The launcher they use, based on Adobe Air is total bonekrs and was even worse at the begining of lol
I used to play in LoL NA, but since the region block I'm now in LoL PH. Haven't encountered problems like that yet. Are you guys still encountering the same issue? I can try bypassing the block and check if I get the same problem. I miss the NA nerd ragers...