Run ScanDisk
By: Arie SlobWindows 98 Setup runs ScanDisk to check the integrity of the drive where Windows 98 will be installed only when you start it from MS-DOS. If you start Setup from Windows 95 and you also want to check the integrity of the drive where Windows 98 will be installed, you should either start Setup from MS-DOS or run ScanDisk manually before you run Setup.
In addition you should also want to check and defragment the entire hard disk drive thoroughly. Be sure to defragment all compressed drives, because a highly fragmented compressed drive reports more available hard-disk space than is actually available. If you use disk compression software other than DriveSpace or DoubleSpace, be sure to run the disk-checking utility provided with your compression software.
Stacker 4.0 from STAC Electronics and similar disk optimization utilities are not compatible with Windows 98, we recommend you get rid of it.