Try this as a possible fix. This trick can quickly fix many mysterious hardware failures
The other thing I've heard of happening is a few of the USB 3.0 ports having problems with USB 2.0 equipment. I know it should be back compatible, but Windows can have problems. Try another USB port to see if that helps.
Does the SeaGate cable have 1 or 2 connections to the computer? Unfortunately, most external hard drives need to connect to 2 USB ports to get enough power.
I just looked up this problem on Seagate's website, and they pretty much come up with the same answers. Uninstall and re-install the USB drivers with the SeaGate connected. Or use other USB ports. The other suggestions they have don't make sense, if you can't talk to the thing, how do you run Seatools or checkdisk?
Fixya doesn't allow me to put in another link at this point, so you'll have to copy and drop this into your address bar.
Here's another write-up on fixing the code 43, I wouldn't do number 6.Update BIOS though, USB is working fine with everything else, it's NOT the BIOS that's having a problem.