after removing virus with kasper sky win xp log off automatically after putting login password,
What to do for resolve it
Even Kapersky isn't perfect ! You could run some other malware/virus scanners, or You might try repair of the OS from the Windows CD. If that does not help, get another HDD and fresh install to it. One can never be sure everything is removed after an infection, and a clean antivirus scan does not necessarily mean everything is a-ok. Then you could use the original drive as a slave to retrieve your personal files, with the understanding of course, there might still be a 'baddie" on it !
This won't work, the logon file change is not a virus, it's the after-effects of a virus. A virus scanner will remove a virus but not the damage that virus causes. And this issues does not always happen with a virus, it can happen with a remote control software like PCAnywhere.