Suggest upgrading to SP3 or later for invalid certificate errors.

chrome/app/chromium_strings.grd

Index: chrome/app/chromium_strings.grd
diff --git a/chrome/app/chromium_strings.grd b/chrome/app/chromium_strings.grd
index 58e7445f0a19626bd6639113b87588d072b3ad29..aa1a5637423314ecfea45e3e7c6874f2de69d834 100644
--- a/chrome/app/chromium_strings.grd
+++ b/chrome/app/chromium_strings.grd
@@ -1263,6 +1263,9 @@ Signing in anyway will merge Chromium information like bookmarks, history, and o
           Chromium can't establish a private connection to &lt;strong&gt;<ph name="DOMAIN">$1<ex>paypal.com</ex></ph>&lt;/strong&gt;. This is probably because your computer's date is set incorrectly (<ph name="DATE">$2<ex>Jan 1, 1970</ex></ph>). You should refresh this page after <ph name="BEGIN_LINK">&lt;a href="#" id="clock-link"&gt;</ph>you update your computer's date and time<ph name="END_LINK">&lt;/a&gt;</ph>.
         </message>
       </if>
+      <message name="IDS_SSL_NONOVERRIDABLE_MORE_INVALID_SP3" desc="Body text for the explanation shown if the user clicks on the details windows, the certificate is invalid and the user has an old version of Windows (before WINDOWS XP SP3) running.">
+      Your computer is running an old version of Microsoft Windows that cannot process this website's security certificate. Because of this problem, Chromium can't tell whether the certificate came from <ph name="SITE">$1<ex>google.com</ex></ph> or from someone on your network pretending to be <ph name="SITE">$1<ex>google.com</ex></ph>. Please update your computer to a more recent version of Windows.
+      </message>
 
       <!-- OOBE -->
       <if expr="chromeos">