diff --git a/browser/installer/windows/nsis/installer.nsi b/browser/installer/windows/nsis/installer.nsi
index 0e509bdb51a..047c3edcc88 100755
--- a/browser/installer/windows/nsis/installer.nsi
+++ b/browser/installer/windows/nsis/installer.nsi
@@ -312,12 +312,12 @@ Section "-Application" APP_IDX
   ${UpdateProtocolHandlers}
 
   ClearErrors
-  WriteRegStr HKLM "Software\Mozilla\InstallerTest" "InstallerTest" "Test"
+  WriteRegStr HKLM "Software\Mozilla" "${BrandShortName}InstallerTest" "Write Test"
   ${If} ${Errors}
     StrCpy $TmpVal "HKCU" ; used primarily for logging
   ${Else}
     SetShellVarContext all  ; Set SHCTX to HKLM
-    DeleteRegKey HKLM "Software\Mozilla\InstallerTest"
+    DeleteRegValue HKLM "Software\Mozilla" "${BrandShortName}InstallerTest"
     StrCpy $TmpVal "HKLM" ; used primarily for logging
     ${RegCleanMain} "Software\Mozilla"
     ${RegCleanUninstall}
diff --git a/browser/installer/windows/nsis/shared.nsh b/browser/installer/windows/nsis/shared.nsh
index 966aae64a6f..2600c098477 100755
--- a/browser/installer/windows/nsis/shared.nsh
+++ b/browser/installer/windows/nsis/shared.nsh
@@ -46,19 +46,32 @@
   ${UpdateProtocolHandlers}
 
   ClearErrors
-  WriteRegStr HKLM "Software\Mozilla\InstallerTest" "InstallerTest" "Test"
+  WriteRegStr HKLM "Software\Mozilla" "${BrandShortName}InstallerTest" "Write Test"
   ${If} ${Errors}
     StrCpy $TmpVal "HKCU" ; used primarily for logging
   ${Else}
     SetShellVarContext all    ; Set SHCTX to all users (e.g. HKLM)
-    DeleteRegKey HKLM "Software\Mozilla\InstallerTest"
+    DeleteRegValue HKLM "Software\Mozilla" "${BrandShortName}InstallerTest"
     StrCpy $TmpVal "HKLM" ; used primarily for logging
     ${RegCleanMain} "Software\Mozilla"
     ${RegCleanUninstall}
-    ${SetStartMenuInternet}
-    ${FixShellIconHandler}
-    ${SetUninstallKeys}
     ${UpdateProtocolHandlers}
+    ${FixShellIconHandler}
+
+    ; Only update the Clients\StartMenuInternet registry key values if they
+    ; don't exist or this installation is the same as the one set in those keys.
+    ${StrFilter} "${FileMainEXE}" "+" "" "" $1
+    ReadRegStr $0 HKLM "Software\Clients\StartMenuInternet\$1\DefaultIcon" ""
+    ${GetPathFromString} "$0" $0
+    ${GetParent} "$0" $0
+    ${If} ${FileExists} "$0"
+      ${GetLongPath} "$0" $0
+    ${EndIf}
+    ${If} "$0" == "$INSTDIR"
+      ${SetStartMenuInternet}
+    ${EndIf}
+
+    ${SetUninstallKeys}
 
     ReadRegStr $0 HKLM "Software\mozilla.org\Mozilla" "CurrentVersion"
     ${If} "$0" != "${GREVersion}"
diff --git a/browser/installer/windows/nsis/uninstaller.nsi b/browser/installer/windows/nsis/uninstaller.nsi
index e700f5125e3..f91b38a9b97 100755
--- a/browser/installer/windows/nsis/uninstaller.nsi
+++ b/browser/installer/windows/nsis/uninstaller.nsi
@@ -221,12 +221,12 @@ Section "Uninstall"
   ${un.DeleteShortcuts}
 
   ClearErrors
-  WriteRegStr HKLM "Software\Mozilla\InstallerTest" "InstallerTest" "Test"
+  WriteRegStr HKLM "Software\Mozilla" "${BrandShortName}InstallerTest" "Write Test"
   ${If} ${Errors}
     StrCpy $TmpVal "HKCU" ; used primarily for logging
   ${Else}
     SetShellVarContext all  ; Set SHCTX to HKLM
-    DeleteRegKey HKLM "Software\Mozilla\InstallerTest"
+    DeleteRegValue HKLM "Software\Mozilla" "${BrandShortName}InstallerTest"
     StrCpy $TmpVal "HKLM" ; used primarily for logging
     ${un.RegCleanMain} "Software\Mozilla"
     ${un.RegCleanUninstall}