Hola
tengo un problema al iniciar el launcher de minecraft, me da este reporte:

Bootstrap (v5)
Current time is Jun 22, 2014 5:19:18 PM
System.getProperty(‘os.name’) == ‘Windows 8.1’
System.getProperty(‘os.version’) == ‘6.3’
System.getProperty(‘os.arch’) == ‘amd64’
System.getProperty(‘java.version’) == ‘1.7.0_60’
System.getProperty(‘java.vendor’) == ‘Oracle Corporation’
System.getProperty(‘sun.arch.data.model’) == ’64’

Looking for update
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 2/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 3/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 4/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 5/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 6/10)
Didn’t find an update in time.
Reversing LZMA on C:\Users\Javier\AppData\Roaming\.minecraft\launcher.pack.lzma to C:\Users\Javier\AppData\Roaming\.minecraft\launcher.pack
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 7/10)
Unpacking C:\Users\Javier\AppData\Roaming\.minecraft\launcher.pack to C:\Users\Javier\AppData\Roaming\.minecraft\launcher.jar
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 8/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 9/10)
Cleaning up C:\Users\Javier\AppData\Roaming\.minecraft\launcher.pack
Starting launcher.
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 10/10)
Exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Recognized exception: the likely cause is a set of broken/missing root-certificates. Check your java install and perhaps reinstall it.
Unable to download remote file. Check your internet connection/proxy settings.

luego se abre el Launcher pero solo me da la opción de jugar offline.

Alguna solución (ya he probado a desinstalar y reinstalar java y a desactivar el antivirus)