diff --git a/app/controllers/contests_controller.rb b/app/controllers/contests_controller.rb
--- a/app/controllers/contests_controller.rb
+++ b/app/controllers/contests_controller.rb
@@ -17,6 +17,14 @@
     end
   end
 
+  def clear_stat
+    user = User.find(params[:id])
+    if user.contest_stat!=nil
+      user.contest_stat.destroy
+    end
+    redirect_to :action => 'user_stat'
+  end
+
   def clear_all_stat
     if not Configuration.indv_contest_mode?
       redirect_to :action => 'index' and return
diff --git a/app/controllers/login_controller.rb b/app/controllers/login_controller.rb
--- a/app/controllers/login_controller.rb
+++ b/app/controllers/login_controller.rb
@@ -10,7 +10,6 @@
     if user = User.authenticate(params[:login], params[:password])
       session[:user_id] = user.id
       session[:admin] = user.admin?
-      UserContestStat.update_user_start_time(user)
       redirect_to :controller => 'main', :action => 'list'
     else
       flash[:notice] = 'Wrong password'
diff --git a/app/controllers/main_controller.rb b/app/controllers/main_controller.rb
--- a/app/controllers/main_controller.rb
+++ b/app/controllers/main_controller.rb
@@ -3,6 +3,8 @@
   before_filter :authenticate, :except => [:index, :login]
   before_filter :check_viewability, :except => [:index, :login]
 
+  append_before_filter :update_user_start_time, :except => [:index, :login]
+
   # COMMENTED OUT: filter in each action instead
   # before_filter :verify_time_limit, :only => [:submit]
 
@@ -319,5 +321,10 @@
     }
   end
 
+  def update_user_start_time
+    user = User.find(session[:user_id])
+    UserContestStat.update_user_start_time(user)
+  end
+
 end
 
diff --git a/app/models/user.rb b/app/models/user.rb
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -16,7 +16,7 @@
            :foreign_key => "receiver_id", 
            :order => 'created_at DESC'
 
-  has_one :contest_stat, :class_name => "UserContestStat"
+  has_one :contest_stat, :class_name => "UserContestStat", :dependent => :destroy
 
   belongs_to :site
   belongs_to :country