Given the fact you don’t wish to download new things it kind of ties our hands as to how to fix the problem. I would start our like Endless asked and ask what color your plug is. If it’s red you can check your connection with the following to the chat server ;
Hold the windows key and press R
Type cmd and hit enter
Type in the black screen tracert of1.kongregate.com
Check for any *’s close to the end of the list of hops, if you’re having a connection based issue it would show here. If it’s not a connection issue I would reset your browser as was mentioned above and then test it. If you’re using Chrome I would highly recommend following the FAQ in how to save your game files and then download the Beta of Chrome and go from there. I would also check for malware that could corrupt files.