There is fatal error getting written in alert log which is --

Fatal NI connect error 12560, connecting to:
(LOCAL=NO)

VERSION INFORMATION:
TNS for 64-bit Windows: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for 64-bit Windows: Version 11.2.0.1.0 - Production
Windows NT TCP/IP NT Protocol Adapter for 64-bit Windows: Version 11.2.0.1.0 - Production
Time: 17-JAN-2013 16:53:14
Tracing not turned on.
Tns error struct:
ns main err code: 12560

TNS-12560: TNSrotocol adapter error
ns secondary err code: 0
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (3740) as a result of ORA-609
Thu Jan 17 17:02:47 2013
Starting background process SMCO
Thu Jan 17 17:02:47 2013
SMCO started with pid=21, OS id=4768