Actually, such a hotkey exists... but is not known by many.
To tell the truth, I discovered this on my own one day, and have been using it since to help people who have rogue scripts loaded or multiple instances of mIRC (trojans/drones) running.
You probably know you can break out of a loop by tapping CTRL+BREAK. This actually simply kills the current command being processed, and usually halts the event. However, if you hold CTRL+SCROLLOCK, it will prevent mIRC from processing ANY commands for the entire duration you have those buttons pressed. This goes for ALL instances of mIRC; active, not active, hidden, or loaded under different users.
If you start your computer while holding CTRL+SCROLLOCK, you can rest assured that no drone clients will activate or connect to IRC servers. If you start mIRC while holding CTRL+SCROLLOCK, none of the On Start, On Load or Perform commands will execute either. If you have an internal PC Speaker, you can tell that it's working if you hear a bunch of clicks.
Spread the word on this one, as it solves SO MANY problems with EVIL Scripts. It also solves the problem of EVIL Timers that perform /editbox -a... impeding a user from typing commands. You can instruct the user to hold CTRL+SCROLLOCK while they type //remote off | timers off, and you don't have to worry about all the worm scripts that perform a DELTREE C:\ when it detects the user doing this.
It's the wonder drug that Khaled/Tjerk forgot to document.
If only there was a way to keep CTRL+SCROLLOCK down without having to actually hold it down.
- Raccoon