I had to start the install CD in safe VGA mode and have not got the slash to display yet.
To get sound to work you don’t need to recompile your kernel or go back to an earlier version just follow method G one this page:
sudo aptitude install linux-backports-modules-generic
sudo gedit /etc/modprobe.d/alsa-base
In the editor, add the following line at the end of the file:
options snd-hda-intel model=dell-m42
Save the file and reboot to get sound working correctly.
If sound is too low, go to Volume Control’s Preferences and add “Front” (and any other playback tracks) and make sure they are set to the maximum.