Hello,
I have a few ideas of what you can try.
- First try to see if clearing the cache helps you at all. Turn off WoW and then in the folder "World of Warcraft_retail_" there is a folder named “Cache”, delete that folder.
2a. Shut down your computer and then unplug your router for 60 seconds. Restart the router and give it 2-3 minutes to be fully up and running, then turn on your computer.
2b. When your computer is up and running press the Windows-key+R or right-click on the Start button and press “Run”. Then type in “cmd” and press ENTER or OK. A third option is go into the Start menu and locate and click “Tools for Windows” and then click the Command Prompt. When you have the Command Prompt open type the following:
ipconfig /flushdns
Then press ENTER and restart your computer. Then you can try launching World of Warcraft again and see if that helps.
If that doesn’t help try this:
- There is a thread on the Technical Support forum that might solve your issues and it seems fairly easy to try it out. The thread is named “Freezing after a loading screen - SOLUTION! /gquit” with the following webaddress/URL:
Further down the thread Turbocolor seems to have a solution to their problem. This is the direct webaddress/URL:
In short Turbocolors solution is:
"… If you go to your guild “info” tab, and click on “Click to set news filters”, there’s a lot of checked boxes.
if you uncheck them, it fixed my freeezes each time i was loading a new instances".
If I were you I would do all steps above 1, 2a and 2b try if that solves it and if not, try step 3.
Step 3 is a bit of a gamble from my part but I have about 25 years experience as an IT-professionell so my solution might work 
(Also the possible solution in step 3 all goes to Turbocolor. I just read it and realized that the long latency (high ping) because of a bug in World of Warcraft can give you very strange problems).