best technical document about patch management

HI,

Every month Microsoft patches are deployed to about 5000+ desktops with Windows 7 32 Bit Enterprise Edition. There is only 90% desktops are getting the patches are installed.

Please let me know how do i troubleshoot remaining 10% desktops which are failing?

What are the best method to analyze the logs and bring the desktops to complaint.

Regards,

Boopathi S