Trace file getting huge

We've a system with Oracle 11.2.0.1 on windows 2003 server. My other DBA has just informed me of one of the problems they are facing. A couple of days back they turned on the following events

> alter system set events '20011 trace name ERRORSTACK level 3';
SQL> alter system set events '29913 trace name ERRORSTACK level 3';

Now they are sure that they disabled the events immediately after that but the key problem is that the one trace file is getting humongous. It has already reached 4GB as of now and still growing. Its not letting delete or open it either.

The interesting part is that the DB has been recycled twice since setting up that event but the file continue to grow.

Alert file doesnt say much except referring to the trace file for a foreground process.

Now my questions:
1) how can we check and confirm that the event tracing that was enabled earlier is off or disabled?
2) How can we stop this trace file and find wut event is actually causing it?

A SR with Oracle is already open since yesterday but they are taking their sweat time in coming back.

Thanks for the help.

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