Wave Profiler (& Playback audio engine) won't run.

First, here's some system info:
SONAR Home Studio 6/6XL, now updated to 6.2.2.
OS:                   Windows 7 Home Premium (64-bit), Service Pack 1
Processor:       Intel i5-3470 CPU @ 3.2Ghz  3.60Ghz
RAM:                16 GB
Internal HDD:  2 TB (only 369 GB used)
External HDD:  2 TB (only 369 GB used; for backup)
Interface:        AKAI Professional EIE Pro
Keyboard:       Yamaha PSR275
Connection:    M-Audio MIDI-to-USB; or MIDI-to-MIDI cables  (keyboard to interface)
 
Current problem: 
My Wave Profiler (& Playback audio engine) won't run anymore.
 
How I got here: 
I was using a MIDI-to-USB chord (M-Audio), to connect my keyboard (Yamaha PSR275), to my digital interface (AKAI Professional EIE Pro), but my COMPUTER SOUND CARD (Realtech High Definition Audio), skipped, or would quit running after about 2 measures.  No big deal, really, because I'd planned to mostly use my interface soundcard (AKAI), anyway.
Then, I just happened to get some MIDI-to-MIDI cables, playing around, to see if SONAR patch/instrument/etc. features would be any different.  They were!  Great, right?
Then I ran the Wave Profiler, in case there was any advantage to optimizing for my new connection.
However, I'd also changed my Driver Mode from WDM/KS to MME, wondering if this'd help my problem of a stuttering COMPUTER SOUND CARD.  It ran ok, and now in Options-Audio, my drivers are different.
 
Any attempt to change any of the settings under Options-Audio(-General, -Advanced, -Drivers, etc.), just default's back to the Options-Audio-Advanced Tab.
 
I've tried:
Restarting SONAR
Restarting Windows
Reinstalling SONAR
Reinstalling the driver for the interface (AKAI).
(Though, it allowed me to reinstall, without uninstalling, first.  Maybe I should've done that, but SONAR says it makes no changes to the ports/hardware/drivers/etc.?)
Creating a new project
(It allowed me to record, but not playback).
Reconnecting the M-Audio MIDI-to-USB cable.
Updating from SONAR Home Studio 6/6XL to SONAR Home Studio 6.2.2
(which claimed to allow problems switching Driver Modes).
No go.  The problem still persists.
 
Granted, SONAR Home Studio 6/6XL & 6.2.2 are older versions, and maybe that's my trouble, given my newer system, but somehow I'm doubtful.
 
Any ideas how to get my Wave Profiler, and Playback audio engine, to run again, would be greatly appreciated.
(Somehow I'm reluctant to spend the money on upgrading to SONAR X3, which may not fix the problem.  Reinstalling didn't.)
(I'm also not really worried about the COMPUTER SOUND CARD stuttering.)
 
Hopefully yours,
CakeMike1