The external hard drive (1 TB) started making a noise last night. It was still working. Today it is still noisy and will not show up on explore at all.

click start control panel administrive tools ,computer management ,device manager look through all of your devices if you see a yellow question mark?or exclamation mark ! or red x
right click to reinstall drivers or
if you can see your usb but its not working
ports(com&lpt)right click update driver
if your computer came with a motherboard disk the drivers could be on it
sometimes the wires inside the cable will be damaged due to bending or stretching or placing heavy equipment upon the cable,
just replace the cable of the hard disk, when you plugged the external disk drive you got that windows could recognize the USB device change the cable everything should work fine again,
check the USB leads that attach to the motherboard usually red-white-green-black make sure they are securely seated and have no dust build up on them dust will cause static and a lot of unforeseen problems
hope this helps

Probably not the right answer for your problem. Mine is an external 1 TB Simple Drive. Mine wouldn't respond at all. I unplugged the power cable from the back of the hard drive and replugged it in and instantly it worked (with the computer and hard drive plugged in). I had tried rebooting the computer, plugging/unplugging over and over into the computer and that didn't work.

Its probably trying to boot from your external drive.

Go into your bios and reset your boot setting to HDD0 as your first boot device, Disk drive 0 second and floppy third, unless you want to boot from an external drive. That being the case select an appropriate order.

If the bios shows your external HDD as HDD0, then you have to work out which is the drive carrying the operating system and set that to your first boot device.

To get into the bios, watch the boot screen for a key to hit to enter setup, normally its the "DEL" key.

check to make sure the power supply( strip/ outlet) is on and no fuse or circuit (GFCI) has been tripped

u mite need a replacement caddy if you are outa your warrenty period i would open it up an test the hard disc drive on another pc if it powers on u need to get ur self a another caddy type in google external caddy

Yes. If the case has been damaged, imagine what happened inside the hard disk, where the tolerances are in microns. Start saving for a new one.

You need to set your boot sequence in the BIOS so that it does not include external drives. Basically your computer is trying to load Windows from the external drive instead of its own internal one. 

Your motherboard manual is going to help, if you can't manage it by yourself give me a link to your manual or tell me the model of your motherboard and i will show you what you need to change.

try going onto computer and see if it has removable disk right click and open or try putting usb in another port or if a disk came with it put that in .

I had the same problem and surprisingly, after many attempts to get the drive to mount with different connections, etc., the problem turned out to be the power adapter. If you've got the same kind of adapter on another drive, switch it out and see if your drive shows up. Good luck.

This is probably a bad sector on your hard disk. Connect it up and try this:
1. Start > Run > type in cmd then click OK to get a command prompt.
2. Type in chkdsk e: /r (replace e: with the drive letter of your external hard drive).