SQL*Plus: Release 11.2.0.3.0 Production on Mon May 20 12:26:29 2013
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Connected.
SQL>
SQL>
SQL> startup ;
ORA-00000: normal, successful completion
you need to investigate more about this error most the cause for this error :
1- Oracle Home contain “/” in the end of detestation.
2- if one not works for you, Then you need to check your networks included with listener
Thank you
Osama Mustafa
Technology Geek 