NT4 USB
 

On NT4 theres no usb (way less than 98)

you can get usb for keyboards/mice and usb memory sticks (maybe more) by installnig a dell update. Says its for optiplex, but it enabled my (fully patched NT4 sp6) IBM thinkpad r30 to use my usb memory stick

its R62200.EXE. Intea01i.exe is also good.

http://ftp.us.dell.com/utility/R62200.EXE
http://ftp1.us.dell.com/utility/Intea01i.exe

works on nearly all intel boards and a few VIA boards , dont know about other ones

downside is you need admin rights, so not suitable for a corporate environment