Hello Roland. Your computer is infected with malicious software. Run an anti virus check on it. I personally recommend Comodo Security, but if cor-el (another contributor here) ever reads this, I'm sure he'll give you a load of links and suggestions. I also recommend you don't type your password while your computer is infect. The probability that is has been stolen already is moderately high, so don't aggravate it and change it as soon as possible.