Hi, Urgently need your help. WinXP Home SP2 with up-to-date update files as well as several antivirus and antispy programs. Firefox22.214.171.124 with No Script enabled. When I got home tonight and turned on the computer, the screen reads: "lsass.exe - system error - An invalid parameter was passed to a service or function". When I closed the message, the computer keeps rebooting so I cannot do anything to diagnose or clean up. Even a safe mode boot didn't help. I also tried google using another computer but so far cannot find anything relevant. This is the first time ever I ran into this problem. Cant figure out why a malware (e.g. Sasser worm?) even got into my computer. I am getting frustrated. Could you please show me what to do next? Thanks a lot for your help.