AM running 64 bit Windows.

I am not aware that I am selecting MIDI, Real Tracks, etc - I just enter chords and play the tune.

Just ran an apdate driver program judt purcahsed that updated 33 of my drivers, including some NVIDEA audio drivers.
Had it restart computer (although not a cold boot) but still same problem with that song,
Maybe I should redo it now.
By the way,. can time signatures (2/4, eg) conflict with certain Styles?
Could that be the problem?