Brush problem in Corel X3 (PhotoPaint)

 I have been using Corel for more than 17 years; first time I have this problem (running Vista Office, Professional): All brush functions are affected: When I left click to anchor the brush, the cursor jumps diagonally up and the line is drawn from this new position to where the brush is currently. See pic. The cursor was at A when I left clicked the mouse, then jumped to B and simultaneously draw the stroke to A.

I reloaded Corel entirely, but problem persists.

Any help?