Last night, my console began to disconnect from XBL after playing for around 10 minutes. Restarting the console would reconnect it to XBL, but after 10 minutes of playing online, it would disconnect again. I also cannot join any XBL parties anymore (before last night, it was limited to just people who's NAT settings were restricted). Also, the console would only disconnect if I was actually playing a game. The console would not disconnect if I played a game's offline content or just let the console sit, despite staying connected to XBL. I went through all the standard troubleshooting associated with XBL problems and yeilded no results. After trying those steps, I tried going directly to the dashboard from a game after I had just been disconnected from XBL. The screen fades to black, the xbox Guide goes away, but the dashboard NEVER shows up (I let it sit there for 15 minutes and it did nothing). If, while it is on that black screen, I try to press the guide button again, the guide shows up, but the loading animation stays and the "friends messages media" etc never show up. Trying to push the guide button doesn't make the guide go away after "opening" it. Trying to hold the guide button to make the console soft-restart doesn't work. There are occasions where pushing the power button on the console also does not turn the console off, and I have to hard-restart it by unplugging the power source.
I thought it would be useless to post this in XBL problems because not only does the problem reach farther than just XBL, but the official support users would just tell me to go through the troubleshooting process again, which I have done twice with no relief of the problem.