Microsoft is aware that after installing the February security updates a limited number of users are experiencing issues restarting their computers. From reports, it has appears that this issue occurs after installing MS10-015 (KB977165). It may or may not be specific to a particular brand of PC or third party software. While Microsoft works on this problem, the update has been removed from Windows Update. Additional details are available at
Windows XP Restart Issues After Installing MS10-015.