cant detect re-formated external hard drive

Looks like a hardware problem to me. Of the last few times I encountered this problem
 - two times the USB cable was broken and
 - two times the media I tried to mount was physically broken (There is a certain brand of UBB sticks that *melts* if it is plugged into a computer running a commercial OS.)
 - one time the Usb controller of my hard disk used timing for the USB communication that made it incompatible with half of my hardware.
 - and one time the USB cable i had to use was longer than 5 meters - which is the absolute maximum the USB Consortium allows.

nope not any of that...thanks though

am using testdisk right now so I'll see what that does for me.

External drives have a bit of a rep for not having sufficient power from the USB port to fully operate the drive.

This is a problem as the original USB spec only allowed 500ma @ 5.5V (If i recall correctly), and many hard drives require >700mA. Manufacturers didn't seem to care about this little detail, and simply sent out these cases into the world, where they simply did not work. Many external cases have separate power supplies to overcome this problem.

This occurs most often on laptops, where power supply tolerances tend to be tighter, especially if you use a standard size drive.

Desktops can have this problem as well, but are less likely to. Some external cases supply a "Y" style USB cable to try to work around this problem, but it falls into the nasty hack category -- some USB ports are on the same power bus, so this defeats the Y cable workaround. (occasionally on a laptop, only the neighbouring ports are on the same bus, so plugging one end into the left hand side of the laptop, and one into the right fixes this.)

Y Cable example:
http://www.bixnet.com/5vps2powercord.html

I have once -- and it is not a bright idea as it assumes a common ground, and thus may fry your hardware -- plugged the Y cable into two separate computers, one for the data, and one for the power (the power cable was identifiable by only having two pins in the USB connector).

If you are able to unmount the drive from the external chassis, try connecting the drive to the computer internally -- often this will magically restore the drive, and thus let you pin it down as a power issue.

testdisk has found the drive and is now letting me restore it....ill let ya'll know the outcome

root@terry-Satellite-L305:/home/terry# /dev/sdc
bash: /dev/sdc: Permission denied
how can I get permission?

done