DOS drivers uninstall procedures
Acturely, the DOS install program will remark old DOS drivers 
in AUTOEXEC.BAT file and add new lines that point to new path
you specify. The two lines list below are the install program added 
in the AUTOEXEC.BAT file.
C:\PCIAUD\SETAUDIO.COM
C:\PCIAUD\C3DMIX.COM ......