Ubuntu 7.04/Issues/Screen goes blank when switching consoles
From DellLinuxWiki
Systems Affected: Dimension E520n, XPS 410n
Description: On a fully booted system, switching from X (tty7) to any virtual console and then back to X causes the screen to go blank.
Impact: Unable to use X
Workaround: Reboot the system.
Fix: Install newer Intel video driver version 1.9.94 or higher currently available in the feisty universe repository. The newer Intel driver that fixes the problem is already installed and should load by default if your system came pre-installed with the OS from Dell.