Live Tablespace restore/rollback to a old state

Environment: Oracle 10g Standard edition (datapump not available), Windows 2003 server

1. How can we restore/rollback to a old state at tablespace level without
. bouncing/shutting down the database
. without export and import

We can take tablspace hotbackup. What I am trying to do is not exactly recovery but rollback to hotback tablespace file. Now while database is up, OS will not let me delete/rename the exisiting dbf file.

2. When we take tablespace export, is it consistent data? -
what is happening to data changes (DML, DDL etc.) while export (or import) is going on.
while importing what happens to exisiting tables which have been overwritten with new definitions im export dump file.

Thanks in advance for helping.

-D

1) Try tablespace point in time recovery, I have never done it, but here is your link,
http://www.lc.leidenuniv.nl/awcourse...2/ostspitr.htm

2) Oracle provides you read consistent image of data when doing export.