It's in the Precopy2.cab on the Win98 CDROM
you need to point to <Drive>\Win98 to extract the file.
GO Start> Run SFC
Choose "Extract one file from installation disk."
In the "Specify the system file you would like to restore" box, type;
[b'Setupx.dll[/b]
(for example)
Choose Start
Choose the "Restore From" box,
Browse to the Win98 Folder on Windows 98 CD (D:\Win98, or E:\Win98, or F:\....etc)
In the "Save File In" box, Browse to C:\WINDOWS\SYSTEM
(or wherever the file to be extracted belongs), and then click OK.
Click OK and then click Yes to restart the computer.
TT4U
Notification:
These are just "my" thoughts....and should be carefully measured against other opinions.
Backup All Important Data/Docs..All involved shall be spared the grief.