This happened to me once after I installed NL. I had sent a sim to Uni and wanted to switch from downtown to playing my campus neighbourhood. It seemed to load but then the control panel started flashing up on the blue load screen and the game froze then crashed. It also totally screwed up my desktop settings so that the wallpaper appeared to have melted and the half the icons were missing! Restarting the pc was the only way I could sort that out. Ive since been able to switch neighbourhoods without issue but Ive never found out what caused the problem.
However, my in game graphics do appear to be screwed in general at the moment.