NSIS detection of a 32-bit process in Win 7 x64

I have a rather common task for my NSIS installer - to find out if Firefox is running before the install, and ask the user to close it. But I haven't yet found a plugin that works for Windows 7 x64. I have tested Processes, FindProcDll, nsProcess - they all failed to detect the 32-bit firefox. I'd be grateful for any ideas where to look next.

Update: Actually, I couldn't detect the 64-bit firefox either wit开发者_运维问答h any of these plugins.

FindProcDLL worked fine for me on 32 and 64bit systems.

I tried to find 32bit process and 64 bit processes and both were fine.

nsProcess works just fine for me. It also seems to be the most recently updated of the plug-ins you listed, so that's why I tested with that one. I'm using Win 7 x64 and confirmed in Task Manager that Firefox showed as "firefox.exe *32"

!include nsProcess.nsh
...
${nsProcess::FindProcess} "firefox.exe" $R0
${If} $R0 == "0"
    # it's running
${EndIf}

Possible return codes:

0    Success
603  Process was not currently running
604  Unable to identify system type
605  Unsupported OS
606  Unable to load NTDLL.DLL
607  Unable to get procedure address from NTDLL.DLL
608  NtQuerySystemInformation failed
609  Unable to load KERNEL32.DLL
610  Unable to get procedure address from KERNEL32.DLL
611  CreateToolhelp32Snapshot failed