Hello,
What version of SEP 12.1 have you installed?
What OS is the Laptop running?
Secondly, check these Articles which may assist you -
Installer Information - "Symantec Endpoint Protection has detected that there are pending system changes that require a reboot." when trying to install SEP 11.0 on Windows 7
http://www.symantec.com/docs/TECH95608
System is in a reboot loop after installing Symantec Endpoint Protection (SEP) version 12.1
http://www.symantec.com/docs/TECH168658
Windows installer is stuck in loop for Installing Symantec Endpoint Protection
http://www.symantec.com/docs/TECH95762
Hope that helps!!