Essentially, the redraw problem is most probably the graphic card. Make sure it's not onboard. Otherwise, your openGL support may be wrong. I had to buy a new card. If you buy a new card, since this is not gaming and will not require a full blown card, any good recent card should do.

What version of bobcad are you using?
seems there was a problem with 19.3 or so for printing. Make sure you have 19.4.4.

I would expect a software at version 19 to be free from that kind of bugs, not so... well... still like it tough...

Para