Why doesn't minecraft work?

This is what comes up whenever I try to start it

Bootstrap (v5)
Current time is Feb 22, 2014 1:36:24 PM
System.getProperty('os.name') == 'Windows 7'
System.getProperty('os.version') == '6.1'
System.getProperty('os.arch') == 'x86'
System.getProperty('java.version') == '1.7.0_51'
System.getProperty('java.vendor') == 'Oracle Corporation'
System.getProperty('sun.arch.data.model… == '32'

FATAL ERROR: java.lang.NoClassDefFoundError: sun/security/validator/KeyStores
at sun.security.ssl.X509TrustManagerImpl.<i… Source)
at sun.security.ssl.TrustManagerFactoryImpl… Source)
at sun.security.ssl.TrustManagerFactoryImpl… Source)
at javax.net.ssl.TrustManagerFactory.init(U… Source)
at sun.security.ssl.SSLContextImpl$DefaultS… Source)
at sun.security.ssl.SSLContextImpl$DefaultS… Source)
at sun.reflect.NativeConstructorAccessorImp… Method)
at sun.reflect.NativeConstructorAccessorImp… Source)
at sun.reflect.DelegatingConstructorAccesso… Source)
at java.lang.reflect.Constructor.newInstanc… Source)
at java.lang.Class.newInstance(Unknown Source)
at java.security.Provider$Service.newInstan… Source)
at sun.security.jca.GetInstance.getInstance… Source)
at sun.security.jca.GetInstance.getInstance… Source)
at javax.net.ssl.SSLContext.getInstance(Unk… Source)
at javax.net.ssl.SSLContext.getDefault(Unkn… Source)
at javax.net.ssl.SSLSocketFactory.getDefaul… Source)
at javax.net.ssl.HttpsURLConnection.getDefa… Source)
at javax.net.ssl.HttpsURLConnection.<init>(… Source)
at sun.net.www.protocol.https.HttpsURLConne… Source)
at sun.net.www.protocol.https.Handler.openC… Source)
at java.net.URL.openConnection(Unknown Source)
at net.minecraft.bootstrap.Downloader.getCo…
at net.minecraft.bootstrap.Downloader.run(D…
at net.minecraft.bootstrap.Bootstrap.execut…
at net.minecraft.bootstrap.Bootstrap.main(B…

Please fix the error and restart.

Re install Java (Also make sure you download Java 7). Also make sure you reset your Router and change the Password. It might also be a problem with your DNS.