We have some excellent members here with great backgrounds, but sometimes 'help' threads can be confusing, so in order to help us help you, I think we should make sure members try to follow something like this:

Please be as specific as possible. Make sure you always provide us with detailed information about the problem. List specific error messages where applicable, or add images if needed. We are here to help but we cannot guess what the problem is.

Also, be sure to include your computer specifications, MacOS version, software version, or any other details that could help us solve your dilemma. If you are unsure of your computer specifications, you can find this by clicking on the apple menu in the top left hand corner of the screen and going to 'about this mac'. For more information on systems, I recommend checking out http://apple-history.com/

Has someone else already had the same problem as you?