Sorry I had to open another thread but the foruns won´t let me reply to messages!I had already stated my problem and Mister Fitzer asked me to answer some questions.Here it goes:
What Country/State/Province do you live in? Portugal
Router brand & model number: Netgear CBVG834G
Network Connection Type: Tried both
Is UPnP Enabled? No but I also tried and it did nothing
Is NAT Type Open? Usually yes
What type of internet do you have? Optic fiber
Who is your ISP(Internet Service Provider)? ZON
When you run "Test Xbox LIVE connection" what is the exact message shown on screen? A problem ocurred when signing in.Then I press for more info and it says that my console is connected to the Internet but can´t contact Xbox Live.
The few times I can connect it disconnects some minutes later.It started happening since the update and I already erased it and downloaded it again.Some days before the update though,I was already receiving the message that a problem ocurred while signing in but I always managed to connect and play well,with an occasional freezing of the console.I also noticed that since last week,it took a lot longer for the console to connect to LIVE.I´ve also been having some problems on my pc,some sites are very slow,like the xbox foruns for example.That´s why I don´t know for sure if the problem is with my router but I have the router firewall turned off and I followed the steps to open the ports on the port forwarding section.