Windows XP Security Policy

Control Panel -> Administrative Tools -> Local Security Settings

Group policy settings: Start->Run-> mmc.exe gpedit.msc

Windows XP – auto logon enable/disable

Start->Run: control userpasswords2  (from Auto Logon to Windows XP)

TweakUI, Registry etc at http://windowsxp.mvps.org/noautologon.htm and http://windowsxp.mvps.org/Autologon.htm