Check the official AMD Support Community under "Legacy Products" or search the /r/FPGA subreddit for "ISE 14.7 modern OS." Disclaimer: This post is for informational purposes. Always download software directly from the official AMD/Xilinx website to avoid malware.
Navigate to the official AMD (formerly Xilinx) support site: https://www.xilinx.com/support/download.html xilinx ise download
Scroll down past the Vivado downloads. Look for the heading: "ISE Design Suite" or "Legacy Software." You will likely see links for ISE 14.7 (the final version). Check the official AMD Support Community under "Legacy