Sounds like some serious packet loss. Either you're running
A LOT of background processes (You can check this by pressing Ctrl + Alt + Delete), you have anti-spyware, anti-virus, or a firewall (Even windows firewall) running in the background, or your connection to HTCs servers is rotten somewhere along the hops.
A DxDiag and PingPlotter output would be useful.
For the DxDiag, go to Start>Run. Type in: dxdiag. Now press OK. Let the application load (Loading bar is located on the bottom left), then press the, "Save All Information..." button. Save the file to a location easy to locate, such as your desktop, then open that file. Copy the
first third (
1/3) of the file then paste it in a response here.
For your PingPlotter results, download PingPlotter:
www.pingplotter.comAfter you encounter another disconnect, run a PingPlotter trace on the Arena's IP Address you disconnected from. Run that trace about 15 minutes. Afterward go to Edit>Copy as Text. Now paste what was just copied to your clipboard in a response here.
Remember, the results of your PingPlotter output will be more accurate if you run them for 15 minutes directly after you're booted from one of the arenas.