Driver for W98 - TT1816 can still be downloaded from www.terratec.com.
I did this and after unzipping I got 6 files in a:\tt1816\window98 including 15_16w95.drw and 15_16w95.vxd. But running "install new hardware" and specifying "have disk" pointing to a: resulted in the error message: "The specified location does not contain information about your hardware". Note that "Terratec" is not on the W98 list of known soundcards.
How can I install the driver