82443EX Chipset (66MHz) : Pentium II 266/300/333MHz Processors
82810 Chipset (66MHz) : Celeron Processor running up to 466 MHz with a 66-MHz system bus.
810e Chipset : PIII 450, 500, 550, or 600-MHz Processors, 100 MHz bus
810e Chipset (PCI only) : Intel Celeron (466 or 500 MHz) or Intel Pentium III (550 or 600 MHz) with 100 MHz bus
82443BX Chipset (100MHz) : Pentium II 350/400/450 MHz or Pentium III 450/500/550/650MHz Processors
At this point, your system is only really useful for running depreciated OS' and playing legacy games.
It would make no sense at all upgrading as even the most inexpensive machine available today is massively more powerful.