There is a very popular website owned by Google, called VirusTotal. The web address is https://www.virustotal.com/

It gives zero hits, including for Norton (Symantec). Here's the direct link and screen capture for mIRC 7.54
https://www.virustotal.com/#/file/7e2ab3...6f10e/detection

Drag & Drop your own mirc.exe file to VirusTotal, or compare its checksum values to those below, to perform your own verification for reassurance.



Code:
    File: mirc_7.54.exe
  CRC-32: 64b49122
     MD5: a2ae6177d4725e30d2508d2d832dbdb3
   SHA-1: 8b817549212750a291fdfa6cb777a522b8b8162a
 SHA-256: 7e2ab3c94f67446732ddb745cda0797dedd686cd74fa06851e1f021c89c6f10e
 SHA-512: d3275e860baa4f193f4caf54703784b2876c1593c50925c315687c5c6960f9d77a7c86f86b46d18f5883936ffde6f7b2791de03b8a19a5a46e50fb84171d98d5
SHA3-256: 60142905eb5bd2f46613d70dfc08841cbdd1b883f028d2ca7b60ae4025fa89cc
SHA3-512: 30c80f24b25a38bd6ab78041baa83f23b7b5c760943d69c2fbfe0cab95d15e75d665650d29486d88587e92c41aab08e1bca61774a0ba379c18d6d8a7b8cfb013

Well. At least I won lunch.
Good philosophy, see good in bad, I like!