Make nsis match better

application/basilisk/installer/windows/nsis/installer.nsi

@@ -1073,51 +1073,22 @@ Function .onInit
     Quit
   ${EndUnless}
 
-  SetRegView 64
-!else
-  StrCpy $R8 "0"
-  ${If} ${AtMostWin2000}
-    StrCpy $R8 "1"
-  ${EndIf}
-
-  ${If} ${IsWinXP}
-  ${AndIf} ${AtMostServicePack} 1
-    StrCpy $R8 "1"
-  ${EndIf}
-
-  ${If} $R8 == "1"
-    ; XXX-rstrong - some systems failed the AtLeastWin2000 test that we
-    ; used to use for an unknown reason and likely fail the AtMostWin2000
-    ; and possibly the IsWinXP test as well. To work around this also
-    ; check if the Windows NT registry Key exists and if it does if the
-    ; first char in CurrentVersion is equal to 3 (Windows NT 3.5 and
-    ; 3.5.1), 4 (Windows NT 4), or 5 (Windows 2000 and Windows XP).
-    StrCpy $R8 ""
-    ClearErrors
-    ReadRegStr $R8 HKLM "SOFTWARE\Microsoft\Windows NT\CurrentVersion" "CurrentVersion"
-    StrCpy $R8 "$R8" 1
-    ${If} ${Errors}
-    ${OrIf} "$R8" == "3"
-    ${OrIf} "$R8" == "4"
-    ${OrIf} "$R8" == "5"
-      ${If} "$R7" == "0"
-        strCpy $R7 "$(WARN_MIN_SUPPORTED_OSVER_CPU_MSG)"
-      ${Else}
-        strCpy $R7 "$(WARN_MIN_SUPPORTED_OSVER_MSG)"
-      ${EndIf}
-      MessageBox MB_OKCANCEL|MB_ICONSTOP "$R7" IDCANCEL +2
-      ExecShell "open" "${URLSystemRequirements}"
-      Quit
-    ${EndIf}
-  ${EndUnless}
-!endif
-
+  ; SSE2 support
   ${If} "$R7" == "0"
     MessageBox MB_OKCANCEL|MB_ICONSTOP "$(WARN_MIN_SUPPORTED_CPU_MSG)" IDCANCEL +2
     ExecShell "open" "${URLSystemRequirements}"
     Quit
   ${EndIf}
 
+!ifdef HAVE_64BIT_BUILD
+  ${Unless} ${RunningX64}
+    MessageBox MB_OKCANCEL|MB_ICONSTOP "$(WARN_MIN_SUPPORTED_OSVER_MSG)" IDCANCEL +2
+    ExecShell "open" "${URLSystemRequirements}"
+    Quit
+  ${EndUnless}
+  SetRegView 64
+!endif
+
   ${InstallOnInitCommon} "$(WARN_MIN_SUPPORTED_OSVER_CPU_MSG)"
 
 ; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be