I am running Draftsight Professional. Last night while working a drawing I noticed the mouse became sluggish, then the screen froze and I ended up loosing the dwg. 2.5 hrs of dwg gone.This morning it happened again. 2 hrs redrwg the same dwg I lost last night. I am now manually saving every ten minute or so. Has anybody experienced this? I have run Norton 360 virus scans and nothing has been detected on the computer.