I am slowly transferring to a new HD screen laptop. I want to audit, rearrange,
etc. whilst travelling in the train. All I need is earphones.
 
I seem to remember being able to use the built-in Sound Blaster with Sonar 4.
It was even described in the manual.
 
When I go to the drivers in SPlat I do not see the built-in Realtek drivers.
Is this no longer possible?

is your onboard sound card enable under device-manager?

Like savoy suggested, first make sure the onboard sound card shows up in device manager and is functional.
 
In Sonar prefs, in playback and recording, what is the driver mode?  If it's ASIO, that's why the Realtek isn't showing up.  Most onboard sound ships like Realtek don't have ASIO drivers.  You can switch to WDM or MME, but most likely the latency will be terrible.
 
As a workaround, download ASIO4all, a free wrapper that will allow your Realtek driver to be used under ASIO, and give you workable latencies.

I only disable any currently unwanted devices/drivers, being careful as to not uninstall them...
 

Hi. Since this is a new pc, I assume it is running Win 10.
I would try WASAPI Exclusive driver mode (Preferences (P), Audio, Playback and Recording), when using the on-board soundcard. 
All the best.
Edit: I have done this on my laptop for a while, with decent result.

Yes, WASAPI Exclusive mode works.
Turns out the chipset is Conexant SmartAudio HD, not Realtek.
But I'm up and running now.
 
Thanks!