I'm not sure if this is a virus or what. I booted up my computer and got onto the boot screen for Windows XP Pro then a window popped up and said: lsass.exe - system error an invalid parameter was passed to a service or function So after you click OK, it reboots and its a cycle of this.. I have already tried Safe Mode, exact same thing happens.. I tried using Windows XP Boot CD, Last known good configuration, that didn't work. I can't get onto my computer at all. If the only way is to reinstall Windows XP, my harddrive is on a partition, is there anyway to not wipe out files on one of the partitions, the one that doesnt have Windows XP files, just personal files. I can't run an antivirus or anything, Windows XP wont boot so I cant run any programs. Thanks for your time and help. P.S. I'm currently using a public computer.