Follow these steps:
1. Shutdown the database(if its running)
2. Mount the database
3. run this command
svrmgr>alter database backup controlfile to trace;
This creates trace file in USER_DUMP_DEST.
4. Edit the trace file and remove header information and
rename this file to say create_control.sql
5. Shutdown database
6. @create_control.sql
7. alter database open

GOOD LUCK