My cd and dvd drive disappeared from "My Computer". How do I get them back? :confused:

I'm assuming you've tried restarting the computer? It could mean that your cd/dvd drive driver is now gone, and you'll have to reinstall the driver... or it could also mean that the connection has somehow gone haywire.

Have you recently hooked up any new hardware or used system tools of some sort?
Did this just happen out of no where or after you had restarted the computer?
Was anything installed recently?

I uninstalled Symantec and rebooted. They were not there after reboot. There isn't even cd/dvd drives shown in device manager.

Try this, even if you have not gotten a error 31, this resolves the issue many times and does no harm to PC by making these changes
You can no longer access the CD drive or the DVD drive, or you receive an error message after you remove a CD recording program or a DVD recording program in Windows XP: "error code 31"