I downloaded DraftSight onto my new computer that is running Windows 8 and it worked great the first time I used it, but I saved my drawing and came back later to work on it and it will not open. The message I get is DraftSight.exe-No Disk, There is no disk in the Drive. Plesase insert a disk into drive F;,. Is this a windows 8 issue or some thing else?  Thanks