I’m unable to provide direct download links for (note: version 13.1 is very old; the latest official classic edition is 15.2, while a new "PE" edition also exists). However, I can guide you to safe, official sources.
"NTLDR is missing" when booting from USB. Solution: You burned the USB wrong. Use UNetbootin or RMPrepUSB. Do not simply copy the ISO. hiren boot cd 13.1 iso download
Once you have the genuine Hiren.BootCD.13.1.iso file (approx 520MB), follow these steps: Hiren’s Boot CD 15