Oracle Protocol Adapter Error

HI, I've just installed Oracle 10 g Express Edit开发者_JS百科ion on to my laptop. The platform is Windows XP SP3. Installation went normally. BUt when I try to get connected to the Oracle database via SqlPlus I get "TNS Protocol adapter error".My laptop is on the network.I'd installed the same database on to a Windows Server 2003 and it works fine. What could the problem be?

I presume this is ORA-12560: TNS:protocol adapter error. The Oracle documentation describes it as a generic TNS error, but there are two very common causes of it.

1. The Windows service for OracleXE has not started, so the database is not up.
2. The Oracle SID is not set.

If the service is started then try setting the SID. In a command window type:

C:>  set oracle_sid=XE   

(or whatever you called it). Then you should be able to connect to the database using SQL*Plus. If this does solve your problem you should probably add it to the environment variables (System info, Advanced tab).