scook
The last version to run on XP was the original release of X2. XP support was dropped with X2a due to updated runtime libraries required for multi-touch support. X2a does not install on XP and AFAIK all newer versions fail too. From the X2a update knowledge base page under installation instructions:

Please note: SONAR X2a is only officially supported on Windows 7 and Windows 8. Installation is not possible on unsupported operating systems, such as Windows 98 & XP. It remains possible to install and use SONAR X2a on Windows Vista though it is not recommended. 

Thanks for the info.
 
I don't have or use a multi-touch device.  I would have preferred an install OPTION to forgo multi-touch and still use my very stable Win XP SP3 platform.  Very simple solution. Disable multi-touch and proceed with the installation.
 
And new automobiles are still using Windows Embedded XP and Windows Embedded Automotive (CE).  Why?  Because they are stable.

Johnny V,
 
I did track down a copy of Sonar Producer 8.5 and installed it today.  Now to compare it to X1.

If you upgraded to windows 10 you wouldn't need that rock solid m audio driver. you could use WASAPI in Sonar.
Don't let technology leave you behind man. Its a lonely road.
PS- Sonar 8.5 isn't going to wow you. it was a stable DAW but it in itself is very outdated.
 I wish you the best.