The full error message in Windows XP is usually something like C:\windows\system32\lsass.exe terminated unexpectedly with status code 128.  Your computer will now shut down in __ seconds.... You are infected with a virus (actually its a worm, but it comes down to the same thing)! It is the W32.Blaster worm, or some variant. There is a security hole in Windows that allows these worm to simply install themselves on your computer without your permission. If you see the message, quickly click on the Start Menu and select Run. Type in cmd and press Enter. At the C:> prompt, type in shutdown -a and press Enter. This will cancel the shutdown count. Now you can repair your system. The first thing you need to do is patch the hole in Windows, by downloading and running the security patch from Microsoft's site. Once that is done, update your antivirus program and scan your entire system. If you don't have an antivirus program, GET ONE NOW! Once the virus has been deleted from your system, reboot and re-scan your system just to be sure everything has been cleaned.