My computer won't recognize the DVD/CD drives in the tower.

Is your cd drive getting power? Check your cables and jumpers on the cd drive. Is your cd drive set to master or slave jumper? Test a different cd drive to the computer. If it works, your cd drive may be bad.

allmyheartsissy

Refer to this link for some help, even if you do not get these particular errors, it often resovles issues with the cd rom and the problem you are having, it will not harm or disable anything you have installed by doing this.
http://support.microsoft.com/kb/270008