I have exactly the same drive as you, a 500GB 7200.10 series. What is happening with your drive? Does it power up, is detected by the BIOS and so on?
My computer would start up fine. Windows would load, and I'd start doing whatever, browsing internet, moving files, anything really. Then the hard drive would go into a constant running state. Bogging everything you tried to do because it was doing whatever. Shutting down the computer would take forever, so I had to kill the power. Upon restart, before Windows loaded, I got the message "Disk read error press Ctrl + Alt + Del to restart."
That's about all there was to it. Sometimes after setting off for a while it would start up fine, passed that message. But soon it would go back to the constant running state. It wasn't a RAM issue as that's the first thing I replaced to no fix. Nor do I think it was disk thrashing, though it might be, as I don't fully understand what thrashing is.
Didn't try the firmware, went ahead and bought a new hard drive (Western Digital 1 TB). Installed Windows and everything is going good since. In some good news, I was able to hook up the Seagate as a "slave" drive and pull everything I needed off it. Didn't have any problems with it constant running then, though I'm not going to trust it for just storage.