In 98 it's called System file checker, I can't remember where it is exactly, hang on while I do a quick search
EDIT:
To start System File Checker, follow these steps:
1. Click Start, point to Programs, point to Accessories, point to System Tools, click System Information, and then click System File Checker on the Tools menu.
2. Click one of the following options:
Scan For Altered Files
Extract One File From Installation Disk
NOTE: If you click Extract One File From Installation Disk, you can specify the file you want to extract.
3. Click Settings, choose the configuration you want to use in System File Checker Settings, click OK, and then click Start.
SOURCE LINK at MICROSOFT