On the FTDI Chip page, scroll down to the Processor Architecture grid. The first line is for Windows operating systems 7-10 (see the * below the grid for specific OS's). In the Comments column on the right, click on the setup executable. Download this utility and follow the on-screen prompts to extract and install the software. Administrative privileges may be required.
On the page, select PC Devices, then choose the driver. 26886 WinXP-Vista-7-8 for older adapters (blue and sliver) or 26887 WinXP-Vista-7-8 for newer ones (all black). If your computer is Windows 8 or 10, make sure that you have USB/Serial adapter that is compatible with Windows 8 or 10. The drivers shown here are compatible with both. Administrative privileges may be required.