How to get AVS to open with MPC-HC?

How do I get an Avisynth file to open with MPC-HC when I right-click it and press "play" in the windows context menu? I accidentally accomplished this in Windows XP but I forgot how I did it. My intention back then was to get MPC-HC to show up in the "Open with" list because it didn't. But then I was satisfied with how useful it was to accomplish this just by pressing "play". I'm on Windows 7 now.
I want notepad to be the default program to open .AVS with but to be able to conveniently open with AVS when I want to.

MPC-HC should show up in the "Open with" menu. If not, you can add it yourself.

Using the play command would require messing with the Registry to manually create that association.

It does show up in open with menu but it's more convenient with the play button. Yes I messed with the registry to do it last time. On Windows XP MPC wasn't showing up in the Open With menu so I was trying to force it in via the registry and accidentally I ended up registering MPC to the Play button in the context menu and I was pleased with this serendipity.

But now I am on Windows 7 and I totally forgot how I did this registry trick.

Something like this:

Code:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\avsfile\shell\play]
@="&Play with MPC-HC"
"Icon"="C:\\Program Files (x86)\\K-Lite Codec Pack\\MPC-HC\\mpc-hc.exe,0"

[HKEY_CLASSES_ROOT\avsfile\shell\play\command]
@="\"C:\\Program Files (x86)\\K-Lite Codec Pack\\MPC-HC\\mpc-hc.exe\" \"%1\""


Assuming the current file association uses avsfile as ProgID. You can see in HKEY_CLASSES_ROOT\.avs which ProgID is used.

Thank you! You are a god. In XP the trick must've been in HKEY_CLASSES_ROOT\.avs but in Windows 7 there is nothing there.
There's no ProgID. Oh well.
Thanks again.

Look at
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.avs\OpenWithProgids

Ah yes, it does say avsfile. Everything is good. Thanks Admin.
By the way, the previous question I asked about working with 10-bit video in avisynth is doable by working with the stack16 trick from dither tools. It's rough but it works.
And I know the question wasn't entirely relevant to KLCP so I didn't mean to clutter up the board.