Xp and .net access to Oracle

I have a system that touches an Oracle 11 DB. Installing on an XP machine (with the Oracle 10G client) I get the following error:
<error>
System.InvalidOperationException: The 'OraOLEDB.Oracle' provider is not registered
</error>

My connection string starts with "Provider=OraOLEDB.Oracle"

At a loss here guys. Any one know of a fix? I only have a few hours before the world implodes around here.....