I don't got 3dfx but I do got WinZip, and I can't put any of the stuff I download into the game. I can't download Fed99, or stadiums, boots, etc. Please help me, How can I do all this stuff properly?
Thank you for your time.

Dont know if I get your question completely, but assuming that you can download but just dont seem to get the stuff in the game:

You have to copy the DATA directory from the CD on to your harddisk in the FIFA 99 directory. Copy your downloaded files to the proper directories and the stadiums, boots, kits and so on in the game will be the ones you downloaded.

Good luck with it.