I just installed DraftSight and found that it will open up some DWG files and nothing will be visible in Model or Sheet Tabs.  Also, The Cross Hairs will vanish when dragged over Graphics Area.  These files will open up in Autocad 2000.

I don't recall this ever being an issue with DWG Editor or 2D Editor.  I figured this was essentially the same package with a new name. 

This was tried on Windows 7 64 bit and 32 bit with the same results.

Computer specs should not be an issue as I use Solidworks daily.