1) Unless your internet is locking up, I doubt it's a router issue. The reason I say this is...When you lose connection in EQ, you can still move around (the game doesn't freeze) but you just can't do anything to interact in the world. However, some FPS games (Half-Life did for me, haven't had issues with UT2K4 so can't say) will totally arrest movement. The only thing I remember is the bobbing of the weapons and being able to move your mouse. However, the game still ran, it was just an internet connection.
2) I had issues with overheating before. Not with EQ, but with Battlefield 2. Maybe that's an issue? You might want to find a program that can tell you your computer temperature and see if it's safe for your system. I don't know the specifics on that kind of stuff, but that might be happening. I remember my computer would kind of "die" for a few seconds while it sorta "shut down" to reduce the temperature, but then it would go back to how it was. Of the available options, I would say overheating is my best guess, but I'm by no means an expert...
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