I think I found a solution. I made several changes at once and things work now.
 
Changed driver mode from WASAPI to WDM/KS.
 
In Configuration file:
      ThreadSchedulingModel 2 (was 1)
      MinimizeDriverStateChanges 3 (was 0)
      ExtraPluginBufs 2048 (was 0 - this is for 2C-Audio's Kaleidoscope plug-in, a hungry, greedy CPU killer)
      DropoutMS 500 (was 250 - for Kaleidoscope)
 
Make sure that in Audio devices, only the RealTek HDA WaveRT output is checked (it is 24-bit).
All the other Realtek inputs (MIC, LINE, MIXER) are 16-bit and screw up the wave profiler settings.
 
Platinum now terminates properly. I tried it several times and restarted and tried some more.
 
I think I'll mark this as solved.
 
I still need to do some refinements for performance reasons, as Kaleidoscope is a monster CPU killer and needs huge buffers to work well. I don't plan to use Kaleidoscope for very much on my laptop, but it is a great way to tweak performance as it can easily consume all the resources of any audio workstation available now.
 

CakeAlexS
Saw MSVCR120.dll. Do you have the latest C++ runtime libraries installed?
You wouldn't be running Visual Studio next to Sonar would you?
Did you get rid of ASIO4ALL? If not do it I suggest. Total uninstall (apparently it can be hard to get rid of?).

Ta.

MSVCR120.dll is 12.00.21005.1 dated 2013-10-04 11:59 PM. I don't know if that is the latest.
I don't have Visual Studio.
ASIO4ALL is uninstalled. No traces left.

"I'm tempted to get a cheap USB audio interface, but that sort-of defeats the portability and simplicity of a laptop."
 
Do yourself a favor now :)
 
http://uk.focusrite.com/product-range/scarlett
 

 
Cheers!!

D*mn you. Alex.
I just bought a Scarlett Solo.
Don't tell my wife.
 
 

!!!!

The Scarlett Solo is very nice.