Computer Running Very Slow After Registry Cleaning

We are running Windows 98 and we recently ran the CCleaner program and also had it clean the registry. We forgot to make a backup copy of the registry and now after the cleaning, everything is running super slow. Something must have been deleted that the computer needs, because now simple tasks like opening My Documents takes 45 seconds or more to open, Internet Explorer takes even longer). Is there are way to fix the registry with whatever was deleted even though we didn't make a backup copy of the registry?

Thank you!