I saw the attached image so strongly accept its not SEP 11.x version.
On SEP 11.x version the Definitions will be saved inside this location
c:\program files\common files\symantec shared\virusdefs\numbered folders with latest date
on SEP 11.x by default it can store up to 3 definitions revisions for backup
This can be modified by http://www.symantec.com/docs/TECH103956
But on 12.1 location is changed and by default it is configured to keep only 1 definitions
C:\Documents and Settings\All Users\Application Data\Symantec\Symantec Endpoint Protection\CurrentVersion\Data\Definitions
or
C:\ProgramData\Symantec\Symantec Endpoint Protection\CurrentVersion\Data\Definitions
On ur case i believe you are running on SEP 12.1 kindly check this path and let me know how many numbered folder you have
C:\Documents and Settings\All Users\Application Data\Symantec\Symantec Endpoint Protection\CurrentVersion\Data\Definitions
Hope this resolve the issue ........
Kindly mark the thread as resolved if this answer suits you....