Hi Suri,
All ready this line is there in sqlnet.ora
sqlnet.authentication_services=(NTS) .

All ready i tried to open
Start - Programs - Administrative Tools - User Manager for Domains

but the user manager for domains is not there under administrative tools.

Give me some more places to check. One more thing.

In services ORACLESERVICESSIDNAME IS STARTED. So my question is how we check the process in nt. Thanks.