If you run an help file from mIRC, for example ircintro.chm, then close that help file, mIRC keeps the file locked (you can't delete the file) if the mIRC help file mirc.chm is still running.
1) run the mIRC help file mirc.chm
2) run ircintro.chm (/ircintro)
3) close ircintro.chm
4) try to delete the file ircintro.chm in the mIRC folder (/run .), explorer says the file is open in mIRC
5) close mirc.chm
6) you can now delete the file in explorer
