how to change the default date (reg. on January 1, 1970 )

 hi dear
 how to change the default date (reg. on January 1, 1970 ) to  reg. on (January 1, 2015) as a default
 where to find the php code
pls help
thank Q

@thevarajah22
It is default date of database, not osclass, so I do not think you can do it, maybe only via modifying of some core files.

so can you help me
how to REMOVE the date (reg. on January 1, 1970 )  from the publish item
just to leave it  blank

@thevarajah22
Add following code to your style.css:
#listing #right .seller .reg-date {display:none!important;}

 SOLVE
 thank you very much