SA password in sql server 2005

i have installed sql server 2005 with sp2 and ‘sa’ password and also checked that
select serverproperty(‘productlevel’) it shows that SP2 but the next day when checked it show that sp2 is not installed and shows RTM instead of SP2 and also the ‘sa’ has been removed is this possible the uninstalling the SP2 can remove the ‘sa’ password or is there is any way to find out.
and another thing that can i install reporting and anaylsis service after the initial installation of sql server 2005.

Thanks in advance.
Paritosh