OK, so the first one, your built-in networking connection is likely wi-fi w/ bluetooth and this would be for bluetooth sound (such as a bluetooth headset) and the second is your 3G Data card, so you definitely are not showing an internal speaker driver.
As for the RtlUpd, it is under the Vista directory, see here:
It is possible the driver just has not installed properly or it could be that it needs another driver that allows communications to the speaker driver so it still could be a driver issue. But worst case scenario is that the internal speaker is physically broken in some way.
Since you are still under warranty I would definitely take advantage of the tech support and see if they have any ideas/suggestions or maybe some test programs to determine if it is a hardware failure.