ok,ok,ok.... this is not that difficult...
if the file is in use , go to the TaskManager and kill the DDHELP process, them you can overwrite the ddsound.dll ....About the DX5.zip you only have to copy all the files above the system32\ and run the dx5.reg, reboot.... The dx6.zip you cannot have the dx5 files,(use the original ones from any servicepack), them copy all to system32\ and run the .exe patch, it will change the version of the d3d*.* files to version 6 so that the software thinks thats the one installed...... peace'a'cake.....