virtualbox.org

I have Ubuntu and I have virtual box installed with it running windows XP home. Its run fine for the last few days however yesterday it started rebooting by itself. XP loads up and then sits there frozen for a minute and then restarts and it just keeps doing this over and over again. Theres no error message or anything, also sometimes XP wont even load. I turn the machine on and it just sits there with a black screen. What is wrong?

Did you read the Forum Posting Guide? Please read it and follow it. You need to give us more information. Any changes to the VM config? Updated VB to newer version? That sort of info.