32-bit oracle client install hangs
You may have some messy registry keys hurting you.  I've filled more than a few swear jars trying to figure out Oracle Client install issues on Windows, so hopefully my pain can be your gain.  I made a couple of blog articles on the matter outlining it all.

I would suggest you remove the existing client first which may require some manual work, then install a new client on the cleaned system.

Hopefully that will help.