You really have not given the community enough information to begin to start helping you and fyi the sound software is probably grayed out because it doesn't detect any sound hardware to utilize, providing your even using windows which we don't even know.
Let us know what hardware your system has to the best of your knowledge, if its a retail computer what model is it, is it an hp or a dell? How old is the system, what pci sound card did you buy, and are you sure your speakers are even working, have you tested them with a cd player or mp3 player or something with a similar connection?
Let us know so we can at least get an idea of the possible problems.