External hard drive errors?

Hey folks, I was hoping you all could help me with this. I'm at my wit's end.

I have a 300 gig external hard drive that stopped working suddenly. I unplugged it and brought it with me on a weekend trip and when I plugged it back into my computer afterward, it stopped working. It would recognize that a drive hard been plugged in and gave me the "usb connection ding" sound effect and showed up in My Computer, but the volume label and all information was lost. It was just G:\"Local Disk" and appeared to be empty.
After tinkering with it a bit, I finally tried moving it to a different USB plug and the symptoms changed slightly. The computer recognized that a device had been plugged in, but it didn't even display in My Computer.
I went in to the Device Manager and deleted the entries for the Mass USB device and the drive (which did not have yellow !'s) and rebooted. When the machine came back up, it recognized the drive, but it's still in My Computer as 'Local Disk'.
I've tried rebuilding the MBR with an app called 'MBRFix' (which is supposed to be the same as the old 'fixmbr' command) and no luck. I've tried activating the drive through Computer Management...nothing.

As it stands right now, the drive is in My Computer as G: and when I try to access it, it asks me to format. The drive is listed in Computer Management as G: at 279.47gb and listed as 'online', 'healthy' and 'active' but there is no file system info listed at the top (it thinks its RAW).

What's next? What haven't I tried, aside from ditching the usb enclosure and plugging it into an IDE?

Thanks in advance,
-~Doc~-