>When I boot up my computer I don't get my CD-ROM drive. It isn't there. Why could this be?
>

Any of a number of causes - loose cables are a frequent cause. Incorrect identification of the CD-ROM drive by the operating system is another, with the net result that the wrong driver is being loaded, or no driver at all is being loaded for it. If it worked at one point and doesn't now, it's most likely the first; if it's never worked under the current OS, I'd check the second.