Q:

Erro ao abrir nova Activity

Estou apanhando aqui para conseguir fazer com que ao clicar em um botão, seja aberta uma nova Activity.
Olhei a documentação do Android sobre Activity, Intent, os métodos para criar e ainda sim, não funciona.
Basicamente, fiz os seguintes passos:

Criei um novo Android XML Layout File com a estrutura da nova Activity
Criei uma nova classe para controlar essa nova Activity
Fui no AndroidManifest.xml e add essa nova Activity lá.
Fui no Main.java e configurei o .onClickListener para disparar a Intent e abrir a tela.

Mas, ao clicar no botão que dispara a chamada da 'segunda Activity', o emulador dá pau.
Onde está o problema?
Segue arquivos para análise:
MainActivity.java
package com.emanuel.teste;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.Button;

public class MainActivity extends Activity {
 TextView lblSaldo;
 Button btSoma;
 Button btSub;
 Button btAjuda;
 int saldo;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    lblSaldo = (TextView) findViewById(R.id.tvSaldo);
    btSoma = (Button) findViewById(R.id.btSoma);
    btSub = (Button) findViewById(R.id.btSub);
    btAjuda = (Button) findViewById(R.id.btAjuda);
    btSoma.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
        saldo++;
        lblSaldo.setText("O saldo é: " +saldo);

        }
    });

    btSub.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
        saldo--;
        lblSaldo.setText("O saldo é: " +saldo); 

        }
    });

    btAjuda.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            Intent itAjuda = new Intent("com.emanuel.teste.ajuda");
            startActivity(itAjuda);
        }
    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

ajuda.java
Essa é a classe que controla a tela que desejo abrir
package com.emanuel.teste;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class ajuda extends Activity{

Button btAjudaVoltar;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.ajuda);
    btAjudaVoltar = (Button)  findViewById(R.id.btAjudaVoltar);

    btAjudaVoltar.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            finish();

        }
    });
}
}

AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.emanuel.teste"
    android:versionCode="1"
    android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.emanuel.teste.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <activity 
        android:name=".ajuda"
        android:label="@string/app_name">

        <intent-filter>
            <action android:name="com.emanuel.teste.AJUDA"/>
            <category android:name="android.intent.category.DEFAULT"/>

        </intent-filter>
    </activity>
</application>

</manifest>

Logcat
05-30 01:24:11.402: D/AndroidRuntime(333): Shutting down VM
05-30 01:24:11.402: W/dalvikvm(333): threadid=1: thread exiting with uncaught exception        (group=0x40015560)
05-30 01:24:11.423: E/AndroidRuntime(333): FATAL EXCEPTION: main
05-30 01:24:11.423: E/AndroidRuntime(333): android.content.ActivityNotFoundException: No Activity found to handle Intent { act=com.emanuel.teste.ajuda }
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1409)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1379)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.app.Activity.startActivityForResult(Activity.java:2827)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.app.Activity.startActivity(Activity.java:2933)
05-30 01:24:11.423: E/AndroidRuntime(333):  at com.emanuel.teste.MainActivity$3.onClick(MainActivity.java:53)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.view.View.performClick(View.java:2485)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.view.View$PerformClick.run(View.java:9080)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.os.Handler.handleCallback(Handler.java:587)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.os.Handler.dispatchMessage(Handler.java:92)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.os.Looper.loop(Looper.java:123)
05-30 01:24:11.423: E/AndroidRuntime(333):  at android.app.ActivityThread.main(ActivityThread.java:3683)
05-30 01:24:11.423: E/AndroidRuntime(333):  at java.lang.reflect.Method.invokeNative(Native Method)
05-30 01:24:11.423: E/AndroidRuntime(333):  at java.lang.reflect.Method.invoke(Method.java:507)
05-30 01:24:11.423: E/AndroidRuntime(333):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-30 01:24:11.423: E/AndroidRuntime(333):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-30 01:24:11.423: E/AndroidRuntime(333):  at dalvik.system.NativeStart.main(Native Method)

A:

Tente alterar a linha:
Intent itAjuda = new Intent("com.emanuel.teste.ajuda");

para 
Intent itAjuda = new Intent("com.emanuel.teste.AJUDA");

OU entao chame assim:
Intent openStartingPoint = new Intent(MainActivity.this, AJUDA.class);

