What are the chances of me having viking ancestry?

Surnames only started in the middle ages and your ancestors came from before that. A Dna test could give you some indication (on the male line) and finding out where exactly your ancestors came from. If its,say,England, if they came from the danelaw or other viking-ruled areas would be a better indication,although most Brits are actually descended from hunter gatherers and neolithic farmers rtaher than later saxons,vikings etc.