I have flexisign 8.6v2, Desay xy-380p plotter Gigawear 26-949 serial to USB cable, windows 7... Does anyone know where the drivers are for the plotter?

Have you used the plotter & cable on XP or Vista? - the Vista drivers should work, the XP drivers may work. You can try installing the software in compatability mode - right-click the installer .exe, select Properties/compatability and choose XP or whatever you know works. Only other alternative is to do a Google search & see if you can find drivers - possibly on the manufacturer's website for the plotter, unlikely you'll find them for the cable, & the software may have an update from the manufacturer. "I've always been mad, I know I've been mad, like the most of us..."