Here are some suggestions for getting the best results from this site.
Give details of the problem. A statement such as "it doesn't work" conveys no information. If it did work, you wouldn't be here. Instead, you should post something like this: "I did A; I was expecting B; but I got C instead." Include the complete text of any error messages you saw and where you saw them: in an application window, a CrashReporter window, a log, or whatever. Also include the steps you’ve taken yourself, if any, to try to resolve the issue. If the problem is of recent origin, did you make any changes to your setup just before you first noticed it? Is the problem reproducible or intermittent? That is, does it always manifest itself when you take a certain action, or only at unpredictable times?
Before posting, ask yourself whether it’s likely that you are the the only person ever to have had this problem. If not, search the discussions for answered questions similar to yours. If you found any relevant information, but it didn't help, include details.
Post in the appropriate discussion area. Usually that means the area for the type of Mac you're using, if the problem is hardware-related, or for the Mac OS version you’re running, if it’s more software-related. Some other Apple technologies have their own discussion areas.