Python code to read registry

Documentation says that EnumKey returns string with key's name. You have to explicitly open it with _winreg.OpenKey function. I've fixed your code snippet:

from _winreg import *aKey = r"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall"aReg = ConnectRegistry(None, HKEY_LOCAL_MACHINE)print(r"*** Reading from %s ***" % aKey)aKey = OpenKey(aReg, aKey)for i in range(1024):    try:        asubkey_name = EnumKey(aKey, i)        asubkey = OpenKey(aKey, asubkey_name)        val = QueryValueEx(asubkey, "DisplayName")        print(val)    except EnvironmentError:        break

Please note, that not every key has "DisplayName" value available.

What about x86 on x64? Use 64-bit Specific Types

What if there's more than 1024 sub-keys in "Uninstall"? Use _winreg.QueryInfoKey(key)

Python 2:

import errno, os, _winregproc_arch = os.environ['PROCESSOR_ARCHITECTURE'].lower()proc_arch64 = os.environ['PROCESSOR_ARCHITEW6432'].lower()if proc_arch == 'x86' and not proc_arch64:    arch_keys = {0}elif proc_arch == 'x86' or proc_arch == 'amd64':    arch_keys = {_winreg.KEY_WOW64_32KEY, _winreg.KEY_WOW64_64KEY}else:    raise Exception("Unhandled arch: %s" % proc_arch)for arch_key in arch_keys:    key = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, r"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", 0, _winreg.KEY_READ | arch_key)    for i in xrange(0, _winreg.QueryInfoKey(key)[0]):        skey_name = _winreg.EnumKey(key, i)        skey = _winreg.OpenKey(key, skey_name)        try:            print _winreg.QueryValueEx(skey, 'DisplayName')[0]        except OSError as e:            if e.errno == errno.ENOENT:                # DisplayName doesn't exist in this skey                pass        finally:            skey.Close()

Python 3:

import errno, os, winregproc_arch = os.environ['PROCESSOR_ARCHITECTURE'].lower()proc_arch64 = os.environ['PROCESSOR_ARCHITEW6432'].lower()if proc_arch == 'x86' and not proc_arch64:    arch_keys = {0}elif proc_arch == 'x86' or proc_arch == 'amd64':    arch_keys = {winreg.KEY_WOW64_32KEY, winreg.KEY_WOW64_64KEY}else:    raise Exception("Unhandled arch: %s" % proc_arch)for arch_key in arch_keys:    key = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, r"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", 0, winreg.KEY_READ | arch_key)    for i in range(0, winreg.QueryInfoKey(key)[0]):        skey_name = winreg.EnumKey(key, i)        skey = winreg.OpenKey(key, skey_name)        try:            print(winreg.QueryValueEx(skey, 'DisplayName')[0])        except OSError as e:            if e.errno == errno.ENOENT:                # DisplayName doesn't exist in this skey                pass        finally:            skey.Close()

As it says in the _winreg.QueryValueEx documentation, you need to pass an already open key. EnumKey returns a string, not an open key.

aReg = ConnectRegistry(None,HKEY_LOCAL_MACHINE)aKey = OpenKey(aReg, r"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall")for i in range(1024):    try:        keyname = EnumKey(aKey, i)        asubkey = OpenKey(aKey, keyname)        val = QueryValueEx(asubkey, "DisplayName")        print val    except WindowsError:        break