i am using oracle 8.1.7 windows 2000

Oracle Sofwtare downloaded from the oracle site.( 30 day renewal basis ) from to

Now i want to appply patches to it. so how should i go ahead with it. from where can i get the patch exe.

Also when u are having liscened copy of oracle and if u want to appy patch what is the procedure . how one should do and how it is done