Well, I am glad that SONAR Professional still works.  I am getting more use out of it now than I did for a number of years.  I did notice that it is not possible to correctly drag loop points when in the piano roll view - they go somewhere else and the looped section gets smaller and smaller.  Is this a known issue?  Probably.
 
I'm using a decade (or more) old Intel Quad Core Q6600 with 4 GB RAM and it's fairly solid.  Sometimes the drums stop playing in the middle of playback (SI Drums).  Not fatal, could be better I suppose.
 
I did also put the Bandlab version on my laptop, and it's not bad, although trying to work on a small screen is fairly frustrating.

The issue with moving loops points doesn't sound familiar at all. Does it work as expected in the Track View? Maybe you have Snap to Landmarks turned on...? Have you restarted your PC lately? Maybe a mouse driver issue or weak batteries in a wireless mouse?
 
For the lost drums, try raising the MIDI Prepare Using Buffer back to the pre-X1 default of 500ms. 250ms is too low for a lot of projects.