The Reason why your sound and mouse wont work in Dos is because you probably didn't load them in the config.sys and autoexec.bat startup files. Now im not sure about your sound card and theres next to no hope for it in Dos now, since you would be very
lucky to find Dos Drivers but for the mouse, go into dos, goto C: and type :
once that opens go to the end of the file and type in :
then exit, save and reboot. Now you should have your mouse in Dos
P.S If you are using NT4, Win 2k, WinXP then this wont work as they done use DOS other than a command prompt in Windows.