This is a script that makes a backup copy of mirc.ini every few hours, saving it to a filename that includes the day of the week. If any of these files get trashed again, you can quit mirc, find one of the backups, and copy it back to the original mirc.ini location, and it should have all your settings changes except any made in the last few hours. I've also used this when I messed up my colors palette.
By default, the script doesn't backup popups.ini because this rarely happens. If you want it to also backup the popups.ini, find the line containing 'pfiles' and remove the semi-colon at the front of it.
To install the script, copy the downloaded file into the folder where mirc.ini is located. Then in the alt+R editor, you can choose /file/load then locate the script.
Also, the 'support' dropdown at the top menu of that site has links to download the default popups.ini
Your antivirus may protest about the file being dangerous, but it's doing that because of the *.ini filename, but it's the same popups.ini that installs by default. You should be able to copy the downloaded popups.ini on top of the damaged one. Best to do it while mirc isn't running.
If you can't find the damaged one at all, look in the lower corner of the alt-P for the filename. If it just says popups.ini it's looking for the file in the same folder where mirc.ini is located. If it says scripts\popups.ini then it's looking in that subfolder beneath the folder holding mirc.ini
sha1 checksum: 0aa982a4f36615b10f6119d2367a026798017ef