What's the problem with my post lol, no one seems to get it at all.
I have multiple help file in my mirc directory (i'm not using application data folder), mirc.chm, the official mirc help file and some others .HLP file, the bug is about .hlp file...
So you need a .hlp file, that HAVE TO BE in the same folder as the mirc.exe.In my exemple, my help file is mirc.hlp but we don't care about the name, we don't even care about what type of help file it is (here, it's a french mirc help file, that group a lot of tuto, old and non used $ident\command etc..).
The /winhelp as a shortcut in mirc, so it's possible to open a help file by calling it's name file as an alias.For exemple, if you have a file called GaisGA.hlp, /GaisGa or /GaisGa.hlp will open the help file.
To reproduce my bug, you need the mirc help file, mirc.chm, and another help file, but a .hlp.
I'm not sure this is for me, but the bug is that when mirc.chm is called one time, you can't open any other .hlp file, with the /winhelp command, or even with the menu Help, only /run file.hlp will work