I have a 500Mb USB Flash Disk that doesn't work, I've tried to format it but as the computer reads the USB as only having 1Mb, I get an error message 'Windows was unable to complete the format." I've tried to doing it through Command Prompt (format g: /fs:fat32), and tried using other various formatting programs for USB Flash keys but they all have the same problem.

What would cause the computer to read the wrong (total) size of the disk (besides for a physical fault, or is that the only possibility)???

I can honestly think of a physical fault with the drive. Was it always like this?

You can try performing an error check by right clicking on it from My Computer, going to properties then the tools tab, then click check now, then click both check disk options and start.