I'd avoid that card which has NO return warranty when sold as-is. The quote below is off that ebay auction. So you could be buying a card that is dead and not able to return it for refund given the shady terms.
Condition: Used, sold as is. "See Pics"
Testing: Although we try to test each item, we do not always have the proper equipment to fully test everything.
Warranty: Our 14 day Dead-on-Arrival (DOA) warranty applies to all items not listed "As Is". See details in returns/refunds.
In relation to if this would work in your system. It would work if the power supply can handle it. You may find yourself replacing the power supply to 350 watts or better to run this video card.
Also to mention if this system is still just the Celeron 2.4Ghz, you will likely find that the CPU is a bottleneck to any games you want to play. You can pick up a Pentium 4 socket 478 CPU cheap to upgrade that system. Although I would suggest replacing this system with something newer as for its hardware is almost 10 years old if not already 10 years old.
The other day I saw a socket 478 Pentium 4 2.66Ghz for sale for just $5.00 with $2.99 shipping on ebay. I have a eMachine that is a 2002 model which was originally a Celeron 2.0Ghz with 128MB RAM when new. I replaced the Celeron 2.0Ghz with a Pentium 4 2.0Ghz and saw an immediate improvement in performance with the extra cache. I also upgraded to 1GB RAM from the 128MB and even got Windows 7 32-bit to run on it for single-tasking due to low ram, although I went through a struggle to get the display drivers to work with the Intel 845GL integrated video. I have since downgraded it back to Windows XP Pro which runs very well on it.
Far better computers can be bought inexpensively new or a good used can be bought that is far more powerful.
I wouldnt invest much money into this computer! And if it were my computer and you can afford to do so, I'd replace it with newer more powerful processing power if you are looking to game on it with modern games.
Lastly PCI is weak for gaming because of the lack of bandwidth for any high end games. I ran into this issue back when I bought a HP Pavilion new in 2001 and it was lacking an AGP port, and only had 3 PCI slots available. I installed a GeForce 4 MX 440 with 64MB RAM and it was horrible for gaming trying to play GTA Vice City. My friend who had a weaker 1.0 Ghz Pentium 3 while I had a Pentium 4, and of which he had a weaker gpu GeForce 2 with 64mb ram AGP slot type video card gamed far better than the PCI bus on mine.