If it ended up outside the display, here are three suggestions:
1. Try adjust the screen resolution, find it and bring it back.
2. Restart AutoCAD (that should take care of it without going to next suggestion)
3. Locate your VLIDE.DSK file (probably within your login Application Data folder), open it with a text editor and find the string *sdb-watcher-setting*. Set APEX to 0, save file and restart AutoCAD.