Windows 7 will not recognize my external hard drive

I had used it before with this computer, for a backup in January probably, but I went to use it to back it up again recently, and it did not work. It does not show up anywhere on the computer, though the drive lit up and started. It's a Seagate Expansion 500 GB USB 2.0 Portable External Hard Drive. It does not show on disk manager. When I plug this into the USB, it shows a yellow flag next to Intel(R) ICH9 Family USB Universal Host Controller-2934 and next to Intel(R) ICH9 Family USB2 Enhanced Host Controller-293A. These work with every other USB device I have tried, though. Seagate says if it worked before then it's not their problem. Does anyone have any ideas?

This is just a guess here, it sounds like the usb cable was unplug with out using the safely remove icon in the notification area. Some times when a device is unplug with out using the safe to remove button, it can render that device useless. Is there a reset button on the hard drive? A reset might help it or a power on/off button. Push and hold down on on/off button for 30 seconds for a reset. To check the device, plug into another usb port on your pc to confirm connection. Also try connecting it to a different Pc and see if it confirms connection.

It sounds to me like your drivers for those devices have gotten messed up or are missing.

Double-click on the device with the yellow flag and select: Update Driver option and see what happens.

If you have the Intel Chipset Driver Info stored somewhere, in a folder format with all the drivers listed inside sub-folders, you can point the update to that folder and it should help.

The following is from the READ ME text file in the Intel Chipset Info Driver folder:

************************************************************
* 9F. INSTALLING THE Windows 7* INF FILES AFTER
* OS INSTALLATION
************************************************************
Some Intel(R) chipset platforms already are supported by
Windows 7* so it may not be necessary to use the INF
files provided by this software to update Windows 7*.

The following steps describe the installation process of
the Windows 7* INF files. You may need to repeat these
steps to update all Intel(R) chipset devices not supported
by Windows 7*.

1. Copy the contents of the
<INF Extract Directory>\XXXX\Win7
directory to the root directory A removable media,
such as a USB flash drive (UFD) or floppy disk (A:\).

NOTE: I use an external hard drive for this, but a USB flash drive works just a good!

NOTE:
XXXX is the directory name for the chipset
of interest. Refer to Section 8 for more details.

2. Close all programs currently running on the system.
3. Click on Start.
4. Select Settings.
5. Select the Control Panel.
6. Double-click on the System icon.
7. Click on the Hardware tab.
8. Click on the Device Manager button.
9. Select "Devices by connection" under the View menu.
10. Click on MPS Uniprocessor PC -OR- MPS
Multiprocessor PC.

NOTE:
Only one of the above items will be
displayed for a given system.

11. Click on PCI bus.
12. Right-click on the line containing the description
PCI standard host CPU bridge
-or-
PCI standard ISA bridge
-or-
PCI standard PCI-to-PCI bridge
-or-
PCI System Management Bus
-or-
Standard Dual PCI IDE Controller
-or-
Standard Universal PCI to USB Host Controller
(This line will be selected.)
13. Select Properties from the pull-down menu.
14. Click on the Driver tab.
15. Click on the Update Driver button.
16. Windows 7* will launch the Upgrade Device
Driver Wizard. Select Browse my computer for the driver software.
17. Enter "A:\" in the Combo Box
18. Ensure that the Include Subfolders checkbox is checked
19. Select Next
20. The window Will Display the Device that was installed
21. Select Close
22. Reboot the system if prompted to do so.