Seagate freeagent 500g usb 2.0 beeps sound

I would say if it was spinning when it dropped, you are probably out of luck. There are services available for platter recovery, but they are quite expensive. Practice the 3 backup policy.

See if Testdisk sees the drive and if so try restore or create a boot sector

the beeping sound is the post system searching for your hard drive and other connected devices
try replacing all the leads that attach to your hard drive
good luck

It sounds like you're not concerned about the data on the drive, just the drive itself.
If that is the case, the drive will still be under warranty. Most seagate drives have a 3-5 year warranty.
Take the drive back to where you purchased it and they can get it replaced for you. Alternatively you can send it to seagate direct, however there may be a minor courier fee.
http://www.seagate.com/www/en-us/support/warranty_&_returns_assistance

Unfortunately, they are designed to void the warranty if opened. But since you mentioned trying different PC's, how about different USB cables, or perhaps a duplicate power supply, perhaps one of these items is the issue. There may be a software issue, in that instance if you can find an imaging program, like Acronis, or Macrium, they may detect the drive and **** the info off of it, in order to get any different results that windows the imaging programs will need to run off of "bootable media"

did you check the cable? or adapter that they are working fine?

Connect the 320GB HDD before switching ON the laptop and try to repair using scandisk option to repair the drive. Also use chkdsk /f option in command line mode.

Revert back for more assistance.

remove hard-drive and put it start in to your computer this sounds hard but isn`t. it sounds as the internal board has gone.

the hard disk is very sensitive for shock, i think your hard disk is dead

I am so happy to say that i HAD the exact same problem.
Its an issue with the drive disk itself. Long story short because i dropped the drive the the disk was no longer able to spin fast enough to start the drive (the beeping sound actually being the disk trying to start spinning.
After spending literally the last 4-5 hours looking for a solution I found a unusual method that basically either works, or it doesn't there's no it kind of works. what you need to do is unplug the drive, then plug it back in and start Vigorously spinning it whilst keeping the drive horizontal (similar to what you would do when your unscrewing a light bulb).
You have to try and do so simultaneously with the beep and it should "kick start" the drive (AND OBVIOUSLY DON'T LET THE WIRE DROP OUT AS YOUR SPINNING IT AS YOUR COMPUTER WONT RECOGNISE IT IF ITS NOT PLUGGED IN).
I Know this method sounds far fetched but put it this way, 15mins ago I was working out how im gonna get hundreds of pounds to restore this drive, Now, i've just finished copying my informations onto a laptop from the drive so i can take this piece of plastic **** back to the shop :D.......
Never again Seagate and Thank God for letting me find a solution.