Make the following changes in the Oracle 10.2.0.3.0 and install after these changes
Extract the Oracle client 10.2.0.3.0 setup from 10203_vista_w2k8_x86_production_client.zip file and make the changes as given below.
Edit refhost.xml from client\Disk1\stage\prereq\client and client\Disk1\stage\prereq\client_prereqs\client location and add following line inside CERTIFIED_SYSTEMS tag.
<!--Microsoft Windows 7-->
<OPERATING_SYSTEM>
<VERSION VALUE="6.1"/></OPERATING_SYSTEM>
<!--Microsoft Windows 7-->
<OPERATING_SYSTEM>
<VERSION VALUE="6.0"/>
</OPERATING_SYSTEM>
<!--Microsoft Windows 7-->
<OPERATING_SYSTEM>
<VERSION VALUE="6.2"/>
</OPERATING_SYSTEM>
Edit oraparam.ini file and add the following part(6.0,6.1,6.2) in the file in the Windows parameter.
Windows=5.0,5.1,5.2,6.0,6.1,6.2