Can't access USB flash drive

I suddenly lost access to a USB flash drive while using my laptop on the road. The laptop went into hibernation; when I woke it up, the flash drive had suddenly disappeared. Plugging it into different USB ports didn't help ... or, for that matter, plugging it into USB ports on a different computer. When I plug it in, Windows sees that a removable drive is available, accurately reports it as a Silicon-Power 64G USB drive in Device Properties, and even assures me that it's working properly. But that's it. I can't check for errors, because Windows reports that it can't access the disk. If I try to access the flash drive with the command line, Windows reports 'There is no disk in the drive.' I downloaded the free recovery tool 'Recuva,' as recommended at: 6 data recovery tools for SD cards, USB drives and more - Computerworld and that didn't help. If anyone has any ideas, I hope you'll share them. My unhappy guess is that I either hire a professional data recovery firm, or kiss the files goodbye.

Did you check whether the pendrive appears in Windows Disk management?

If it does appear, please post a screenshot of it.( At the moment I am not convinced that it could be a drive letter assignment problem....If it were so it should get a drive letter assigned and show up on any other PC which you have said not.)

In all probability when your laptop went into hibernation, your pen drive got corrupted. But of what sort we have to decipher.

Thanks for the responses. I always get a drive letter in disk management, but that's all. I wrote before that the problem came on suddenly, and it did ... but also should have mentioned that it acted up once before. It was my own fault for ignoring the warning! I think I've got a physical problem, along the lines of what's described in: https://www.youtube.com/watch?annota...&v=BwvsbUOKGLY ... and am going to chalk it up as a lesson learned. I'll put less faith in USB sticks in the future.

You might want to try HDD Raw Copy Tool as this tool also supports low-level duplication of USB Flash drives for data recovery. If it still have no avail then you might have a better chance of getting your files back with a pro data recovery service at a reasonable cost.