I put in a disc. My computer use to recognize and autoplay the disc (CD & DVD's) Now, it does nothing. When I search in files, the drive isn't showing up. When I look in Run, Nothing again. When I insert the disc, I hear it running like it is starting, but nothing happens. After searching here, I found possible solutions like turning on the D drive; but how? Then, troubleshooting the hardware, but that didn't work. Can someone walk me through solutions to try?

First let's test the CD/DVD drive :

Try this to see if the drive is viable at all (you will need to make these on another computer since your's will not start - XP, Vista, Windows 7 or 8/8.1 or even running Linux does not matter). You could also try booting with another Windows disk - any OS though do not use it to try to ANY repairs unless it is absolutely the same version of Windows on your system - just boot to see if the drive works.

Setup/Settings (BIOS/CMOS) often F2 so watch the screen as you boot - set the boot order to CD/DVD first. Remember to set it back when done.