External hard drive Help?

I connected my external hard drive to my new Dell, it's a PD2500s HP external hard drive. I just want to get my hard drive working. When i connected it, Nothing happens at all, i looked for it everywhere on this computer it. No help bubbles, Nothing on the devices tab, nothing in control panel, or even under my computer. It will not show up any where on this computer. I would love to have the files that are on it. So I searched online for the drivers, for help, or anything but I haven't come up with anything helpful. So i Hopefully i can get some help here.

Thanks for any help.

Try connecting it to another computer first to see if it is seen in "computer". The supplied cable for usb 2 has two usb plugs which must both be connected to supply enough power to run the drive. Try plugging a usb mouse into the sockets in turn to see if the sockets are faulty. If you have any alternative usb sockets available try them. Look in "device manager" for any problems with usb, a yellow ? will show a fault. No specific drivers will be required for an external usb powered drive.

That's why I wish the would make external drives with their own power supply. Or mobo vendors make a dedicated usb slot for external drives. This would simplify a lot of the confusion on the power issue side of it.

Press Win+X then click on Computer Management->Disk Management
You'll see a list of Hard Drives connected to your PC, Do you see it there ?

EDIT: If it is a brand new external HD, you need to initialize it first for it to show up under my computer. If it is an old drive, then use another USB cable or use another USB port or both.

USB 3 has enough power to run a 2.5 hdd (with usb 3 interface) using only one plug. I forgot to mention to Tempest that his cable might be the problem.