B/r

The DB is in NoArchive Log mode & all the Online Redo Log Files are lost. How to recover whole db. What files need to be restored.

Here are some questions that will help you troubleshoot and solve your situation.

Logs were lost when? Database open or closed? What is a cold backup? Are online redo logs copied for a cold backup? If you think not, then why do you need the current ones? If you think so, how can you recover a database using commands that involve manipulating redo logs? How do you make new online redo logs?

http://tahiti.oracle.com
Do a search on backup, cold backup

if you are sure the db was shut down cleanly before the logs were lost
you can issue

recover database until cancel using backup controlfile;

alter database open resetlogs;