Applying 10.2.0.4 Patch 42 (January 2011)

Release 10.2.0.4 for Microsoft Windows (32-Bit)
You should administer one Oracle product, one Oracle home at a time, for its particular Bundle Patch Update. Each Oracle home will have its own requirements. We are updating Oracle Database as below.

Upgrading from 10.2.0.1 to 10.2.0.4 (Win)

Oracle 10g Release 2 (10.2.0.4) Patch Set 3 for Microsoft Windows (32-Bit) 

Identify the Oracle Database Installation
This is not a complete software distribution. You must install it in an existing Oracle Database 10g Oracle home. To identify Oracle home directories, view the/etc/oratab file.