Are you saying your password was changed? Like, you'd enter your password and it'd tell you that it was invalid? Did it just sign you in without requiring any password or fingerprint? If any of these are the case, go to google and search up "spybot search and destroy". it's a freeware program that'll get rid of spyware. It could also be a virus. I wouldn't be surprised if you're using the anti-virus that came with the comptuer. They're never good. I'd go get AVG and spybot. That's what I use to protect my computer. Also, try turning off exceptions in the windows firewall and see if that helps.
If it's not spyware or a virus, then it's probably a glitch in the windows vista operating system. If I were you, until they come out with a second service pack for vista, I'd go find a friend or someone who could format it to xp pro for me. I'd be happy to do it for you, but I'm sure there are plenty of qualified repair techs in Germany so you don't have to spend all your savings shipping the thing to the US. One thing about repair places though, sometimes they give you illegal versions of software. Ask them a question about licensing. if they stutter or seem confused, then stay away!
Anyways, hope for the best that it's just some hacker or simple spyware application running around and not a glitch in the vista OS. They didn't do too much consumer testing with vista so I wouldn't be surprised if it's got a glitch. I do hope for your sake that it's just a virus or some other measly threat. Best of luck to ya.
