MicroStation v8i ss3 (on a Macbook Pro) lines not displaying

Hi

I would be really grateful to receive some help on a frustrating problem I'm having with Microstation.

I have just installed (for the first time) Microstation v8i on a Macbook Pro (OS Mavericks) that has Parallels and Windows 7 installed on it.  When I try to draw a line it just shows up as two tiny points - one at the start and one at the end of the line.  Similarly for a shape, circle, smartline etc it just shows the nodes.  I have tried changing the line thickness, type and colour but this does nothing.  It is possible to select the line or shape and when I do it highlights the handles at each end, so I know there is something there.  

Additionally when I do a print preview it shows the line or shapes as solid, which is great but I can't draw much without being able to see what I'm doing as I go along!  I have tried opening an existing drawing file from another project and this is showing in the same way.  i.e. only the points underneath where a handle would be are visible, but with no line in between.  For a line this is a small dot at the start and end and for a curve it is a series of small dots.  

I've tried changing the view attributes and the display styles but this hasn't made any difference.

If someone can help resolve this for me I would be SO grateful!

Many thanks in advance

RPMBP