mIRC still comes with the old style .hlp files which I can't read on windows 7. Any chance of new help files being written?

Huh? No it doesn't, and it hasn't for years.

if you look at the error message that Win7 pops up, it will lead you to Here , where you can download a program called WinHlp32.exe for a variety of OS versions (8.x, 7, vista, Server 2k8)

How old is your copy of mIRC?
The help files have been in .chm format since v6.21 that I know of, and maybe earlier than that. (and Windows 7 can open .chm files)