If you installed to the default locations, they should be in your "Documents" or "My Documents" folder, depending on your operating system. In my Vista box, they're at: C:\Users\John R\Documents\TurboCAD 16\Drawings. Click on the "Save In" list button, it will tell you where you're currently saving to. Mouseover a thumbnail in the History pane and a tooltip will show the address for that drawing.
Designer, Deluxe, Expert, Basic, Platinum
Windows 10 Pro, 64-bit