When using the Launcher it goes as far as showing the mojan screen and changes the icon on the task bar to look different to the launcher Icon. Then it crashes and goes back to the launcher - and in the development tab I get a Java Run time error and referred to a file on my system that holds the details for reporting bugs.

the error is as per attached text file

I have gone to the Mojang Technical website and used the checker there and this just refers me back here to the Minecraft BUG REPORT JIRA system saying my bug hasn't been reported yet.