for windows 98 you might need to go to the website and see if there is a driver made for it as last time when flash drives come out, they came with disk. today since most of it is plug and play, no disk comes with it anymore
Windows 98 is so old that it natively doesn’t support flash drives and u need to dnld the driver for the flash drive. I faced the same problem earlier that was about 5 yrs ago , and right now I could not remember the driver name/ website name from where I downloaded the drive(probably the driver name is nusb33e.exe) so that worked for flash drive on 98 OS. However, I provided a link, u may try to dnld the drive, but I have not tested due to shortage of time.