After comparing the sound card model number #CT5803(engraved on the card itself) to a list at Creative's Support website, it appeared the card was the Soundblaster Audio PCI 64. However, the card came as part of a refurbished Gateway computer (bought about 5 or 6 years ago). According to the Gateway serial number #6001502 (printed on a sticker stuck onto the card), it was not an Audio PCI 64 but an Audio PCI 128.
Model No. CT5803http://us.creative.com/support/identifyproduct/Serial No. 6001502http://support.gateway.com/s/SOUND/6001502/600150201.shtmlAt first, I thought Gateway must have labeled the card incorrectly with the wrong serial number and that I had been installing the wrong drivers accordingly all these years. However, Gateway support incredibly has images of all their products on their support website listed under its respective serial number. My card matched the image of the card listed under the Gateway serial number and was in fact the Audio PCI 128 and not the PCI 64.
Well I figured out the problem. The sound card was from Creative but had been altered by Gateway/Dell for their product (my refurbished computer). And here's the text from the Gateway site which finally pinpointed the source of my sound problems...
"This is the Creative Labs Digital Audio PCI sound card, part number 6001502. It is meant for use with only the Kadoka motherboard. On the graphic, click the hyperlinks for more information."