New Inspiron 1525 N Volume Control Problem

Just received my new 1525 Inspiron with Ubuntu pre-loaded. While the sound/volume technically work, it is extremely glitchy:

• If I try to use the volume slider in the upper-right of the top panel,  the only two positions that can be chosen are 100% or 0%.
• If I double-click on the volume control, I can update the left channel volume fine.  Even weirder is that it seems to set both the left and right channel volume.  However, if I try to set the right-channel volume, the only two options are 100% or 0%.  I also can't link the channels together (my guess it that the issues in the bullet above are caused by the main panel control using the linked option).

As a result, I cannot easily adjust the volume on the fly... or from aother applications (e.g. Totem, etc.).

My laptop came with Ubuntu 7.10 pre-loaded (would have preferred 8.04/Heron by the way).  I'm new at Linux, so while I pulled all the available updates, I didn't want to try upgrading to Heron until I I felt a little more comfortable.  Other than pulling all of the available updates from the Update Manager, I haven't changed anything.

Tried to do a little troubleshooting on my own... only thing that seemed like it might be odd is that if I go to System->Preferences->Sound, the only "Default Mixer" listed is "Conexant HSF (OSS Mixer)", which wasn't what most of the online help suggested should be there... but may be normal for a DELL 1525N.

Hopefully, it isn't because of a bad sound card or something.  Any advice you can provide on how to get this issue resolved would be greatly appreciated.  Thanks!!