diff --git a/copyvios/checker.py b/copyvios/checker.py
index ca96932..57e2085 100644
--- a/copyvios/checker.py
+++ b/copyvios/checker.py
@@ -56,8 +56,11 @@ def _get_results(query, follow=True):
         query.action = "compare" if query.url else "search"
     if query.action == "search":
         conn = get_cache_db()
-        use_engine = 1 if query.use_engine else 0
-        use_links = 1 if query.use_links else 0
+        use_engine = 1 if query.use_engine != "" else 0
+        use_links = 1 if query.use_links != "" else 0
+        if not use_engine and not use_links:
+            query.error = "no search method"
+            return
         mode = "{0}:{1}:".format(use_engine, use_links)
         if not query.nocache:
             query.result = _get_cached_results(page, conn, query, mode)
diff --git a/copyvios/misc.py b/copyvios/misc.py
index c073d2d..dfb70ae 100644
--- a/copyvios/misc.py
+++ b/copyvios/misc.py
@@ -15,10 +15,12 @@ class Query(object):
     def __init__(self, method="GET"):
         self.query = {}
         if method == "GET":
-            parsed = parse_qs(request.environ["QUERY_STRING"])
+            parsed = parse_qs(request.environ["QUERY_STRING"],
+                              keep_blank_values=True)
         elif method == "POST":
             size = int(request.environ.get("CONTENT_LENGTH", 0))
-            parsed = parse_qs(request.environ["wsgi.input"].read(size))
+            parsed = parse_qs(request.environ["wsgi.input"].read(size),
+                              keep_blank_values=True)
         else:
             parsed = {}
         for key, value in parsed.iteritems():
diff --git a/templates/index.mako b/templates/index.mako
index a17be30..4d7f6cd 100644
--- a/templates/index.mako
+++ b/templates/index.mako
@@ -10,6 +10,10 @@
         <div id="info-box" class="red-box">
             <p>Unknown action: <b><span class="mono">${query.action | h}</span></b>.</p>
         </div>
+    % elif query.error == "no search method":
+        <div id="info-box" class="red-box">
+            <p>No copyvio search methods were selected. A check can only be made using a search engine, links present in the page, or both.</p>
+        </div>
     % elif query.error == "no URL":
         <div id="info-box" class="red-box">
             <p>URL comparison mode requires a URL to be entered. Enter one in the text box below, or choose copyvio search mode to look for content similar to the article elsewhere on the web.</p>
@@ -101,9 +105,9 @@
                         </td>
                         <td id="cv-inner-col2"><label for="action-search">Copyvio&nbsp;search:</label></td>
                         <td id="cv-inner-col3">
-                            <input id="cv-cb-engine" type="checkbox" name="use_engine" value="1" ${'checked="checked"' if (query.use_engine or not query.submitted) else ""} />
+                            <input id="cv-cb-engine" type="checkbox" name="use_engine" value="1" ${'checked="checked"' if (query.use_engine != "") else ""} />
                             <label for"cv-cb-engine">Use&nbsp;search&nbsp;engine</label>
-                            <input id="cv-cb-links" type="checkbox" name="use_links" value="1" ${'checked="checked"' if (query.use_links or not query.submitted) else ""} />
+                            <input id="cv-cb-links" type="checkbox" name="use_links" value="1" ${'checked="checked"' if (query.use_links != "") else ""} />
                             <label for="cv-cb-links">Use&nbsp;links&nbsp;in&nbsp;page</label>
                         </td>
                     </tr>