190 P is connected to the computer hard drive and power supply cables are switched on, but there is no signal showing power to the screen

follow these steps:

1. Make sure the computer and external hard drive are powered on.
2. Safely remove the drive from the computer (if possible).
3. Disconnect the external drive's USB or FireWire cable.
4. Disconnect the power supply plug from the external drive.
5. Power off the computer.
6. Disconnect the computer's power supply cord for 60 seconds.
7. Reconnect the computer.
8. Power on the computer.
9. Connect the power supply to the external drive.
10. Connect the drive's USB or FireWire cable and check for detection.

If that does not correct the behavior, and if the drive is also not detected by your computer, the blinking light is probably a symptom of a larger problem. If those steps do not return the drive to correct function, it is very possible, even probable, that the drive has failed and needs to be replaced

All SATA drives need a signal cable and a power cable, but usually these cables already exist inside your computer waiting for you to use provided that your motherboard allows for an additional drive.

Working previously is good.
Ok, a quick list of the things i have done wrong in just this circumstance.

Is the power supply plugged in and switched on?
Is it supplying power?
Is it supplying the correct voltage?
*Note: You will need a multimeter to do this. 12 Volts is the correct voltage.
Is the power supply plugged into the drive? All the way?
Is there a power switch on the drive? Is it in the on position?
Is the data connection plugged in? All the way? The computer end also? All the way?
Does the cable run from the computer to the drive, or are there other cables lying around two of which are plugged in at one end?
Are you using the same data cable you did before?
Does it work with different cable?
*A caution here. Not all cables are equal. You want to use a USB 2.0 cable.

If it was working before, any one of those could be the problem. I've had them all.

Trying the easiest solution first - It sounds as if the power is getting to the hard drive, but the information is not getting to the computer.

Is the IDE/SATA cable attached to the hard drive AND the motherboard?

Are the connections tight?

Is one end of the cable reversed - does pin 1 on the hard drive correspond to pin 1 on the motherboard?

Are the jumper settings on the hard drive set properly - Master/Slave/Cable select?

Are you replacing an IDE hard drive (uses a wide thin ribbon cable) with a SATA drive (uses a narrow, fatter cable). Can your motherboard handle a SATA drive? Perhaps you are trying to install the incorrect hard drive?

1 . Shut down the computer. Unplug all cables and peripheral devices.

2 . Remove the computer's side panel. (Cases vary. Some will require a small Phillips screwdriver for removal and others feature screw less designs. Please see your case manual if you are unsure.)

3 . Locate the newly installed hard drive. Check that two cables are running from the hard drive to the motherboard and to the power supply. If you see only one cable or if either of the cables are not securely seated, plug in the appropriate connector(s).

4 .
Leave the case's side panel off for now. Reconnect the power cable, monitor cable, and keyboard and mouse connections.

5 . Restart the computer. Enter your BIOS immediately. (Your BIOS usually alerts you to the key required to adjust settings. If your screen does not show this information or if you are unsure, consult your motherboard manual.)

6 . If it is an IDE hard drive, enter the IDE settings. The BIOS should show the hard drive. Configure it as primary or secondary, according to your computer's configuration. (If you have only one drive, set this to primary. Otherwise, set as secondary.)

7 . Save your settings, and exit the BIOS. Once you are certain that the the PC is recognizing the hard drive, replace the side panel.

Thanks.

check power to the monitor.
If monitor is powered and signal cable is connected to the PC display jack, you may have to open the case and reseat the video card. Or the memory modules, or the power supply connectors.
Sometimes a device can cause a PC to act this way. If above does not work then disconnect hard drive, cdrom and floppy connections from the motherboard
and try again
or It could be a bad power supply

Unplug power cable from of the PC. Then hold power button in for 30 seconds, this will drain the capacitors, then plug back in the power cable see if this helps, if not could power supply, or video card.

if you are not getting any broken noise from the hard disk its not ded so ushut down the computer first then connect the hard disk to the power and then connect the hard disk to your system in the usb 2 port then connect the start the system if still dosent detect go to manage by right clicking on the my computer icon the go to disk management check your hard disk shows ther if shows forign just right click on the forigen and say import forigen hard disk if shows the drive helthy and dosent show up on my computer then just right click on the helthy place and say change drive letters and choose one of the letters and should show up on the my computer if still dosent see at all then change the usb cable....
if still dosent work remove hard drive from the external case and put it directly to your computer for this u need a sata cable and a sata power if it detects and work this way your data is safe but you casing of the external hard drive has probs ...
thanks

External Hard Drive is mostly of the USB interfacing type. If urs one is the same, then it is just as simple as plugging in a pen drive in the USB port. If it has external power supplies then u can easily figure out how to connect. There are two parts in the power supply (if external power supply cable is provided), 3-pin main power supply connector and other is the adapter which goes to the external hard drive.plug in the other end of the adapter into the hard drive (there is a hole in it). connect the main power cable to the adapter extension. now for the usb Hard Drive, connect the USB cable to the USB port of the computer. Switch on the power supply to the Hard drive and u r ready to use ur brand new External Hard Drive. If it is a Firewire interfacing one then u may need to open the CPU box, and then connect the firewire connector on to the motherboard firewire port. It is easy to identify, it is a red colored port/connector.

usb cable provides power to your hard drive.

try to use new cable.

hopes it works.

pls. confirm