From the Wiki, try number 6 first if it applies to you.
"I can log into the Server Select screen, but when I try to connect, the screen goes black and then goes to the login screen again.
There are multiple reasons that could be causing this. Here are some of them:
1. Most likely you are running the wrong version of Everquest. Only Legal copies of Everquest Titanium completely unpatched will work.
2. You may want to try other servers to make sure that it isn't a problem on that particular server.
3. If you live in a dorm or are playing at work, you might be using a proxy that is blocking port 5998, which means you won't be able to connect.
4. If you are running a P2P or Torrent program, it might be using all of your bandwidth. Try turning them all off.
5. You may have a firewall that is blocking EQ. Disable all firewalls.
6. If you are running a Dual Core CPU or Windows Vista, you will probably need to read the following post and apply at least one of the fixes listed in it:
http://www.eqemulator.net/forums/sho...t=25327∞
7. You may need to adjust your Windows Desktop and/or your Everquest Resolution settings.
8. Make sure your drivers are up to date for your Video Card.
9. If you have sound enabled, make sure your sound card is working.
10. Try resetting your router. If that doesn't help, try connecting your PC directly to your cable/dsl modem and see if that helps."
Threaded Mode
