I bought this program as I have been drawing for years with Windows cad and Quick cad. They worked great on the older windows system but when we upgraded to 2000 xp we started having problems with lock ups. I took a chance (as Autodesk bought out those companies) to see if I could access my older .cad extension files. This program will load the old files and save them in a .cad format or the .skf which it normal saves files. The only caution is once you have loaded and saved in the Auto desk auto sketch, you can't go backwards. Your old software will not be able to read it. A good drawing package for a good price.