I upgraded win nt 4.0 to build 2151, and installed the dx7 patch, and direct sound and direct input worked great. I know they worked because in quake I could use -primarysound parameter and _snd_mixahead 0.025 and it clearly used the primary buffer, and also I could use -dinput and mouse middle button would work fine. However, I installed the same build again, over the old 2151, and after installing dx7 patch direct input and direct sound weren't working I have tried installing them a few times, but it doesn't help. So, there really can be problems even though you haven't run into one.