Slow Web Pages

I have a Win98 PC that is part of a NT network that has a frac T-1 it uses to access the internet. Before that he was using isdn line. The user “accidently” restored an old copy of his registry and since then when pulling up any site, there is a delay in finding the site and even loading it. There must be a setting in the Registry that is setup for the Old Connection(isdn)configuration. Any ideas on how to find it and/or fix this issue without performing a Format and Clean Install of Windows onthe hard drive.
All other computers on network work fine.