My computer cant find my external hard drive

hello,

erase the oldest back up,right -click delete.

http://www.seagate.com/support/external-hard-drives/desktop-hard-drives/onetouch-iii

You need to check it with Norton Utilities. I hope you still have this hard drive (this posting is posted 5 years ago) and it is not dead yet, so you can copy all of the valuable files to your other data storage.
Here is the link to download the 30 day trial (free):
http://download.cnet.com/Norton-Utilities/3000-18512_4-10907620.html

You did well to have it work so long!
It is out of warranty - open it up, remove the drive from the case. It may be a SATA drive, but probably an IDE from 4 years ago...

Just place it in your computer and it should work fine. The most common problem is the controller card for the external connection has failed. so putting it in your computer as a normal drive will either fix it - or tell you that the drive has died.

diconnect 40 g while install windows on the 250g seems like it is picking up windows off the other one while installing

Please Make sure you External Hard disk USB cable is working correctly. Your cable is probably having partial contact, so try another cable

option 01. try the unit on another windows pc. if its the same. i am afraid you might have an issue with the device.

option 2 . you could remover the **** from the enclosure & fix it directly to the pc so that you can retrive the data. however this will have an impact on your warranty

It should be plug and play on USB2 ports, WindowsXP and above. Install latest service pack of your OS.
Make sure that external power of Maxtor is properly connected.

asss

If files you are trying to restore are encrypted you will have to use same software to retrieve them.. If not, any file in the external hard drive should be viewable with your windows explorer.

And U do not need drivers for external hard drives. They just plug into your usb port and work with modern OS after the unit is recognized.