Yahoo! review: Internet/firewall 81

I, once again, couldn't sign in to yahoo! Messenger. I've been through this repeatedly and it's not getting fixed. I've talked to tech people, some helpful and others not, and all I get are temporary solutions. Most recently, the program completely froze and had to be ended. I restarted it and surprise, surprise, I couldn't sign in. I tried several methods before finally contacting tech support. The woman told me to turn off my firewall that already had an exception for yahoo! But I was cooperative. I turned it off for a moment, signed in successfully, and turned it back on. As an experiment, I logged off and logged back in. Everything was fine. Until today. Apparently turning off the firewall like that kicked my mother's laptop off our internet connection and now she can't reconnect. Our internet doesn't even appear in her wireless networks list. Tech support didn't ask if I had other computers. Didn't warn me about anything bad. Not even the slightest hint! And yahoo! Messenger is still being a complete spazz!