|"Hah, Windows 98 doesn't even recognize USB input."|
It DOES recognize USB input if Win 98 drivers can be loaded.
Regarding mass storage devices -
Windows 98SE and previous Microsoft operating systems have NO built in support for recognizing flash drives; Windows ME was the first Microsoft operating system that did.
It used to be flash drives came with Windows 98, and/or, more often, 98SE drivers that you could install, but that's no longer the case. You can still download 98SE drivers from a few flash drive manufacturer's web sites, but I've found these drivers to be a better solution.....
If you're not sure whether you have Windows 98 or 98SE, RIGHT click on My Computer - Properties.
Whether it is 98 or 98 Second Edition is shown on the right on the first page you see.
Generic USB Mass Storage drivers.
These allow many USB devices that have no drivers for 98 and 98SE to work in those operating systems.
Win98 original, modified from the 98SE version.
"Remove ALL drivers for USB flash drives in Device Manager"
NOTE that I have not had to Un-install previously installed drivers.
If you want to do that, those are listed in Control Panel - Add/Remove Programs.
The 2.x versions support the recognition of many USB devices.
The 3.x versions also support the recognition of USB 2.0 controllers.
NOTE that the 2.x versions have NO Un-install; the 3.x versions DO - in Add/Remove Programs.
After you have installed these drivers, after you have plugged in or installed a USB device that hasn't been plugged in or installed before, you are prompted to have Windows search for drivers - do that, it will find the drivers, and that same USB device is detected automatically when it's plugged in or installed after that.
These drivers work for many devices, but there are some they can't detect.
E.g. Apple never made drivers for their devices for previous to Windows 2000, so an iPod , iPod Shuffle, iPod Nano, etc., cannot be recognized.