diff --git a/setup/installer/windows/wix.py b/setup/installer/windows/wix.py
index aac599ad23..b89a402641 100644
--- a/setup/installer/windows/wix.py
+++ b/setup/installer/windows/wix.py
@@ -14,10 +14,9 @@ from setup.build_environment import is64bit
 WIXP = r'C:\Program Files (x86)\WiX Toolset v3.8'
 if is64bit:
     UPGRADE_CODE = '5DD881FF-756B-4097-9D82-8C0F11D521EA'
-    MINVERHUMAN = 'Windows Vista'
 else:
     UPGRADE_CODE = 'BEB2A80D-E902-4DAD-ADF9-8BD2DA42CFE1'
-    MINVERHUMAN = 'Windows XP SP3'
+MINVERHUMAN = 'Windows Vista'
 
 CANDLE = WIXP+r'\bin\candle.exe'
 LIGHT = WIXP+r'\bin\light.exe'
@@ -42,7 +41,7 @@ class WixMixIn:
             ProgramFilesFolder = 'ProgramFiles64Folder' if is64bit else 'ProgramFilesFolder',
             x64                = ' 64bit' if is64bit else '',
             minverhuman        = MINVERHUMAN,
-            minver             = '600' if is64bit else '501',
+            minver             = '600',
             fix_wix = '<Custom Action="OverwriteWixSetDefaultPerMachineFolder" After="WixSetDefaultPerMachineFolder" />' if is64bit else '',
             compression        = self.opts.msi_compression,
             app_components     = components,
diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index 21da8b7209..d4d8227f7a 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -14,7 +14,7 @@ ORG_NAME = 'KovidsBrain'
 APP_UID  = 'libprs500'
 from calibre import prints
 from calibre.constants import (islinux, iswindows, isbsd, isfrozen, isosx,
-        plugins, config_dir, filesystem_encoding, DEBUG)
+        plugins, config_dir, filesystem_encoding, DEBUG, isxp)
 from calibre.utils.config import Config, ConfigProxy, dynamic, JSONConfig
 from calibre.ebooks.metadata import MetaInformation
 from calibre.utils.date import UNDEFINED_DATE
@@ -926,6 +926,14 @@ class Application(QApplication):
         self._file_open_paths = []
         self._file_open_lock = RLock()
 
+        if isxp:
+            error_dialog(None, _('Windows XP not supported'), '<p>' + _(
+                'calibre versions newer than 2.0 do not run on Windows XP. This is'
+                ' because the graphics toolkit calibre uses (Qt 5) crashes a lot'
+                ' on Windows XP. We suggest you stay with <a href="%s">calibre 1.48</a>'
+                ' which works well on Windows XP.') % 'http://download.calibre-ebook.com/1.48.0/', show=True)
+            raise SystemExit(1)
+
     def load_builtin_fonts(self, scan_for_fonts=False):
         if scan_for_fonts:
             from calibre.utils.fonts.scanner import font_scanner