External Seagate 1 TB HDD suddenly needs formatting

Okay, so this is how it started. I had my Android tablet (Acer A500) hooked to my x64 Windows 7 PC, to transfer a file to it. After that, I tried to safety remove it, but since it uses MTP, it was not in the connected devices list, so I accidentally safety removed my Ext HDD, a Seagate 1 TB HDD with a power outlet. Since the PC said it's safe to remove the hardware, i removed the HDD, and my tablet, and hooked the HDD back on, but ever since, my computer says it needs to be formatted... while my tablet that has a USB port, and on Linux Ubuntu on my computer, it's recognized and it works fine. I've also tried another computer, running x86 Windows 7, but it doesn't work on that one either. I tried changing USB ports, no game, I also tried a reboot... no dice. I've also tried removing it in device manager list and installing it back, but it didn't help.

Please help me, I've got over 800 GB of precious data on my HDD I can't afford to lose. Since in works on Android and Linux, I don't think it really needs a format...

Here you go sir, it's shown as RAW. Like I said, it works fine on Linux... really weird problem.

Okay, so I ran chkdsk /f for this drive and it was fixed. And all my files are there, safe and secure.