Windows 7: Lost external drive

Hello,
I am using Windows 7 Pro. I did an upgrade this morning and when the desktop restarted, I lost an entire external drive. It showed the drive letter, but told me that in order to use the drive, I would have to reformat it.
I tried the same drive in a Vista laptop with the same results.

What happened and how can I fix this?
Pardon me for being skeptical (Vista user), but is this going to happen again?

Please help.

Thanks,
J

Did you have the drive plugged in during the install?

I think perhaps the wording was misleading. What occurred was right after a Windows 7 "update", not upgrade. I have had Windows 7 for a few weeks and installed their software updates. And yes, the device was plugged in for the updates.

Apologies if there was any confusion...

J

just some basics... but unplug the drive power and usb cable. Reboot your computer, then plug the drive back in. Maybe go into computer management and uninstall the drive, then do a rescan.

Thanks, but 'been there, done that..'

J

Open an elevated command prompt and run chkdsk /f X: , where X is the letter of the drive