I got something on my windows XP machine a while back and I can't get it off. When I boot up, a box comes up and says "file not found - lsass.exe". If I click on OK, it reboots. If I allow it to boot and then click on the x and close the dialog box, it allows me to use the computer. How can I get this off my computer? It eats up memory and slows things down.