There is no disk in drive E, when there is one.

I have been using a usb flash drive sucessfully for about a month but now when I want to access the drive in My Computer, the drive is there but when I click on it, I am told to format the disk when I click yes I am informed that there is no disk in drive E and it can’t format. I have gone into device manager to troubleshoot and I have disabled, uninstalled the device but nothing works. I have used the flash drive on other computers and it works. What can I do?