I performed a clean installation of Ubuntu 12.04 (on a laptop with Intel Core2 Duo CPU T7500 @ 2.20GHz and 2 GB RAM), overwriting the previous version. During the installation I decided to install updates and third-party software. The installation was completed without problems, I rebooted the system and after rebooting I checked for updates: the update manager has listed 361 updates to download and install: a bit strange, I'm sure I selected the option to install them during installation... However, I confirm downloading and installing updates. So far I have not configured any wireless connection, but I used an ethernet cable.
After the system update I restarted the system and I have configured my favorite programs and the wireless connection. And from this moment, when I reboot the system, the screen goes blank and nothing happens: I expected the restart for almost half an hour (during which remain on the power light and fan), but then I have to turn off the laptop via the power button.
The problem occurs only when the wireless card (Intel Wireless WiFi 4965AGN) is on and the Internet connection is active (even with the kernel 3.2.0-23), while the problem does not occur if I connect with ethernet cable. Why? How can I fix this?