Did you ever find a solution? My laptop stopped recognizing flash drives, but recognizes other USB devices.

My USB Webcam becomes unrecognized after a week or 2 and then I need to plug it into another USB port. All other devices work. Sometimes the port starts working again. Anyone have any ideas?

I had problems once like this, apparently my HDD was going bad and it had corrupted the registry. So USB flash drives stopped working in that computer. It would say that it was installed and ready to be accessed but it did not show as a drive in my computer. I was able to look at the data but only by right clicking on my computer, going to manage --> disk management, I could see the drive there but it had no drive letter assigned. So I assined a letter and then right clicked on the drive and then went to explore. I had to get a new HDD eventually.

try this.
Right click on my computer and click manage and then select disk management.Choose your USB drive and delete the partition and format it as FAT.