After you complete the boot process, open device manager.
Right click on My Computer and select properties.
Click on the Device Manager tab.
Select the option to view devices by connection.
Find the Yellow "?" or "!" mark that identifies the hardware problem.
Now, copy the information as to how the device connects to the system and post it back here as a comment.
Reject our answers so that we know you have posted the new information.
Then, we can start directing you to the device that needs an updated driver.
Other things to check:
Does your sound card work properly?
What about your USB ports?
DVD-ROM drive?
External storage device such as a flash memory reader?
These are "common" devices that Windows 98 cannot find and install the driver for on it's own.
Chas