Guide Lines disappear

[E Cush]

Having a similar problem here. It started while trying to draw a triangle onto a flat surface to copy/flip/paste as the basis of a dormer on a house. After laying out the coordinates with Tape Tool, I drew out the first right triangle. The guides shifted as though it was slightly under the surface, and fazed in and out as I navigated. When I attempted to copy, the entire surface was highlighted. This is an enclosed geometry issue. I sent all layers to the default and attempted again to confirm. Same problem. I then noticed that the guide was shifting not just in and out of view, but to the left and right of the line drawn onto the guide.

The issue seems to be progressive. I just upgraded from A 8800GTS 512m to a 650ti 2g about 2 weeks ago and have completed about 15 projects maxing at about 6000kb. This only begun last week, and is occuring in the begining of the project at about 2000kb.