If you absolutely cannot go online to activate, you need a scene release. These are and may contain malware. Use only trusted sources (e.g., archive.org user uploads with many downloads/ratings).
Run StarCraft.exe . It will ask for a CD-key. Because you are using version 1.18, any valid 13-digit key from the original game works (the check is local, not online). If you don't have one, a quick Google search for "StarCraft Antares CD key" will yield keys that work for offline single-player and LAN. starcraft 1.18 offline installer
for older standalone patches (like 1.16.1), as later versions have shifted toward launcher-based delivery. Playing Offline: What You Need to Know If you absolutely cannot go online to activate,
While the launcher is convenient, it has downsides for specific users: Run StarCraft
You need to be online to "check in" or update.
While Blizzard’s official direct links have mostly been redirected to the Remastered installer, several reputable gaming repositories still host the original zip files. Step-by-Step Installation: