Querying Wow64 registry keys from a 64-bit Python

KEY_WOW64_32KEY gets the job done

import _winreg

key = None
KEY_WOW64_32KEY = 0x0200

try:
  key = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, \
    r"SOFTWARE\Microsoft\VisualStudio\9.0", 0, \
    _winreg.KEY_READ | KEY_WOW64_32KEY)
  val, type = _winreg.QueryValueEx(key, "InstallDir")
  print val
except EnvironmentError, ex:
  print ex
finally:
  if key:
    _winreg.CloseKey(key)