40GB portable Hard disk !!!

I assume this is an internal hard drive. If it is not being detected by windows, you need to go to disk management. refer to this link to learn more about disk management : http://www.theeldergeek.com/disk_management.htm
When you are in the disk management menu, you need to create a partition and format this partition (if the disk is new). If the disk already has data in it, then disk management will make Windows recognize the drive.

The hard disk is not detected, inaccessible or unreadable because of possible hardware failure, corruption and/ or I/O errors.

To troubleshoot this issue, restart the computer or rescan the disk to try and return the disk to Online

To rescan the disk, open Computer Management, and then click status. Disk Management. On the Action menu, click Rescan Disks.

Just make sure ide cable is fixed properly to the hard drive when scanning.

i have a Hitachi external USB hard disk 320 GB it was working fine at may laptop but when i tried using it with the computer ; the windows cannot detect the USB Drive . i tried it with 2 computer . but its still the same .pleas help i badly need my files

Can you try connecting it to a different computer?
If it still does not work, then you have a "hardware" problem.
Remove the disk-drive from the enclosure, and temporarily attach it as a "slave" disk-drive in a desktop computer, to see if bypassing the USB-to-disk-drive interface will bypass the problem.

Connect ur device to your computer through a usb cable. If your device shall be detected as a portable Hard disk drive. You can see that by checking My computer.OR you can start the windows media player, once you have connected your device to laptop/ computer. It shall automatically give you an option to sync music

Right Click on My Computer, click on Manage, go to Disk Managment, if the drive is available you will see it there. Check to see if it has a drive letter assigned to it, if not right click on it and choose Change Drive letters. Make sure you are on the external drive though, you don't want to change your C drive accidentally. It should pop up in My Computer.

Check the BIOS setting, make sure the hard disk is set to Auto (detect) or change the settings to default settings (your BOS may not have this option) then save and reboot laptop.
If the hard disk has not been detected and/or Unable to find the operating system, it means you may have a faulty hard disk or a faulty hard disk controller or the hard disk may not be making proper electrical connection.

To reseat the hard drive, remove the hard drive and reinsert it into the laptop a few times and see if it boots up..
If it still does not see the hard drive then the fault is probably the hard disk. To test if the hard disk is faulty, remove the hard disk and insert it into a hard drive USB adapter and connect it into the USB port of a working computer. If you don't see this drive as an external drive then you will know its faulty. Then you will need to purchase a hard drive, insert it into your laptop then install the Windows operating system and all your device drivers and programs to get your laptop operational again.

If the hard drive is OK the the fault is with the disk controller, and it is near impossible/expensive to repair the motherboard. Put your money towards a new laptop and put the hard disk into a USB hard disk adapter case and use it as as a portable external hard drive.

Best of luck.

XP install is not detecting any hard disk.
No jumpers are required for laptops, can only have one hard drive in a laptop.
Check the BIOS for the hard disk configuration, make sure that it is set on Auto (detect).
You may have a faulty hard disk, you can check it by booting up with a floppy DOS boot disk, run fdisk to see if it detects the hard disk, OR connect this hard drive to a USB hard disk adapter and connect it to a working computer's USB port and if it detects it as an external drive the it is OK.

Actually if the hd is corrupted, you can try to go to safe mode or do a chkdsk and then fix boot otherwise you need to contact drivesavers for that.

Id recommend trying these following steps: Go to: Start - Control panel - Administrative tools - Computer management - Disk management. Here you should be able to see the 40GB hard drive. Depending on your situation you may need to create a partition, to do so right click the unallocated space and choose to create a partition. The default settings will be fine. Good luck!