Hi,
Thank you for posting in Symantec community.
What is the operating system?
Check the SEP_Inst.log file under %temp% directory.
In a text editor, open the log file that the installation generated.
To find failures, search for the following entry:
Value 3
The action that occurred before the line that contains this entry is most likely the action that caused the failure. The lines that appear after this entry are the installation components that have been rolled back because the installation was unsuccessful.