I had this problem with a certain graphics card. I have installed Alibre on at least 6 computers and 2 of them I swapped the card in to check. The problem followed the card so I replaced it and the problem was solved.
I've spent a week trying to install a new card and my computer doesn't
seem to want to accept it, have done it by the book,litterally, and
nothing but errors, can't disable onbord vga card thru software and
compaq says it should work along with many others so i am going to just purchase a newer model and dedicate it to my cnc system anyhow
thanks for the reply, i did try a different vga card in case that
was it .