automatic reset every 12 hours

[nibor]

in my php made game. I'm having trouble on how it would automatically reset and refresh players stats every 12 hours. the reset file i made which codes are below. It only works when i manually run that script which is going to reset.php file. Can someone please help me out, , want it to reset from server time 0:00:00 and every 12 hours, it would refresh again automatically.

[code]
$a=mysql_query("SELECT id,name FROM members");
while($b=mysql_fetch_array($a)){
$msg="A New Day Has Come, You Have Been Awarded <b>500</b> Buds";
mysql_query("INSERT INTO news (who,message,date) VALUES ('$b[id]','$msg','".time()."')");
}
mysql_query("UPDATE members SET bank=bank+500");
mysql_query("UPDATE members SET daysplayed=daysplayed+1");
mysql_query("UPDATE clan SET age=age+1");
mysql_query("UPDATE members SET stamina=maxstamina");
mysql_query("UPDATE members SET powerball=maxpowerball");
mysql_query("UPDATE members SET life=maxlife");
[/code]


Thanks
- saizen

[.josh]

setup a cron job to run it every 12 hours