How can you tell if your computer has been hacked? I run Mepis on mine and my wife runs Windows XP on hers. Someone made an unauthorized purchase with my bank card and my guess is that they got the number from one of our computers.

There are lots of stuffs and registery of your computer which doen't work well when your computer had been hacked. There are many application which might get disturbed and don't work in a proper way