If the usb plug is loose on the back of an external hard drive, and has worked less and less, now not at all, can anything be done to replace it? Is this something that can be fixed so my external hard drive will work again? The plug has gotten looser and looser over time and now will not work at all. Please help or let me know if there is anything that can be done if its out of warranty. Thanks in advance.

SOURCE: SimpleTech hard drive not found by my computer

if you are running windows, then check the following:

go to control panel -> administrative tools -> computer management -> storage -> disk management.

you probably have a drive (located on the bottom right) that is listed with no drive letter, just assign it a drive letter and see if it comes back, if not, the drive is probably not initializing and you might have to either format it or replace it.

SOURCE: Computer not recognizing my external hard drive...

Make sure you have the power adapter that came with the unit. That was the problem with mine. Now it works fine.

SOURCE: USB external hard drive driver

SimpleTech Tech Support gave me the following instructions this afternoon and it worked for me on my computer running Vista.
Start>Ctrl Panel>User Accounts. Select the option "Turn User Account Control On or Off". (You will probably get the security prompt that asks you to "continue" if you started this action...click "continue".) Locate and UNCHECK the checkbox beside "Use User Account Control (UAC) to protect your computer. Click ok. You will be asked to restart your computer. It worked like a gem for me...hope it does for you too!

SOURCE: Computer won't recognize hard drive and I have a lot of data

I devised these simple steps that tend to remedy quite a few issues with most portable / external hard drives (though not always)
A few things to check but assumes USB and Windows for other interfaces / operating systems similar steps may be adapted to suit.

1. Ensure it is connected directly to the computer to a USB 2.0 port not a USB 1.0 port as this can have effects on performance and reliability
2. Use only the cables that came with it NOT one that fits that may have been lying around or is longer. Not all USB cables are equal even though they should be)
3. Do not connect through an external USB HUB unless that hub is USB 2.0 AND has its own power supply.
4. Use ONLY the power supply that came with it if it has an external power supply
Don’t use any other unless you know it has both the same voltage and current rating e.g. 12V 500mA anything rated below that would not work properly.
5. Always use the same port for connecting your devices. Some devices do not like being switched about. If switched they may want to install software / drivers again.
If you checked and fixed anything there and still have issues carry on reading.
Go to your control panel and then administrative tools, select Computer Management.
Now select Disk Management and expand the window.
Your drive should be listed here, if not then you need to check your computer hardware has not got any issues before proceeding.
If your drive is listed and says healthy then right click on it an select Properties, click Tools and then Error Checking, Check now, tick the two boxes and then Start.
This will attempt to fix most minor / common errors on the drive. It may also ask you to restart which is fine. Allow it to finish its work or you could corrupt the drive. If all went well you should be able to use it normally again.
If you drive was listed but did NOT say healthy then right click and select Format. Choose NTFS as the file system and do not tick any boxes you do NOT want quick format. Again start and let it do its thing. When it is done restart your computer and you should be good to go.
If you still have problems with the drive you might want to look at other areas.

SOURCE: Simple Tech 250 GB external hard drive won't work

I devised these simple steps that tend to remedy quite a few issues with most USB portable / external hard drives and OTHER devices (though not always)

A few things to check but assumes USB and Windows for other interfaces / operating systems (mac/ Linux) similar steps may be adapted to suit.

1. Ensure it is connected directly to the computer to a USB 2.0 port not a USB 1.0 port as this can have effects on performance and reliability

2. Use only the cables that came with it NOT one that fits that may have been lying around or is longer. Not all USB cables are equal even though they should be)

3. Do not connect through an external USB HUB unless that hub is USB 2.0 AND has its own power supply.

4. Use ONLY the power supply that came with it if it has an external power supply Don’t use any other unless you know it has both the same voltage and current rating e.g. 12V 500mA anything rated below that would not work properly.

5. Always use the same port for connecting your devices. Some devices do not like being switched about. If switched they may want to install software / drivers again. This can be especially true if you move a HUB to another port

If you checked and fixed anything there and still have issues then check your hardware from CONTROL PANEL / SYSTEM / HARDWARE.
Any exclamation marks by hardware need fixing before you investigate any further

USB flash drives can fail for no apparent reason.
Sandisk Cruzers are especially bad for this.

USB hard drives should be treated with extreme care.
This is a real hard drive ! and knocks and bumps can quite literally kill them.

It is possible to remove drives from the enclosures in most cases and connect directly inside a PC to fully check it.

Note that if you hear a drive clicking or pinging this could be the worst thing you would hear.
Known as "The Click Of Death"

If none of the above steps help look at updating the drivers from the manufacturers web site in the support section.