Problem Accessing Sandisk USB Drive in Windows 8

I have a 32 GB SanDisk USB drive for almost an year.Did not have any issue accessing it with Windows 7 and now with Windows 8.But suddenly from the past week I have this issue where in system becomes slow, the drive does not open in explorer, no chance to format as well. Cant even safely remove as the icon does not display the drive name. Same case with Sandisk usb drive of my neighbor.What can be the issue? How to resolve