System: Lenovo P50, Win 7 Professional

Draftsight 2018 X64 SP3 Freshly downloaded and installed multiple times.

In sheet space, I cannot see any geometry at all unless I zoom in; as I zoom in, more and more of the geometry becomes visible, appearing as a wipe from the right side of the screen to the left side of the screen. As I zoom out, geometry disappears from left to right. If I center-click+drag the entire sheet to the left side of the screen, more and more geometry appears. If I center-click and drag the sheet to the right side of the screen, more and more geometry disappears. The dividing line between visible and invisible geometry changes as the drawing is zoomed or panned.  

Our var had me install the solidworks video driver rather than the nvidia driver, but all that accomplished was to make draftsight complain about the driver. When that didn't fix it, they instructed me to contact draftsight directly. But as this is a free copy of draftsight, they do not offer any support at all.

I've only used draftsight for about 5 years, but this issue has been the same all along. Any thoughts?