Usb external hard drive is recognize but won't open wants to format

If there's a contact broken or loose, it probably won't format. That you may be able to fix. If the heads have been knocked out of alignment, you're looking at a dead drive. A data recovery service would likely be successful, but they are expensive.

If the drive is being recognised then you are lucky. using data recovery software such as get data back should do it, it costs but its a small price to pay compared to how much it will cost to get it done by professionals. Alternatively search for free data recovery software, i think there was a linux based dvd that has great free softwares.