How can I format my thumb drive so that I can be read by Samsung Galaxy Tab tablet I have a  Samsung Galaxy Tab with an usb adapter. 
how can I format my thumb drive so that it can be read by Samsung Galaxy tablet when attached?
And it also need to be readable by Windows OS so that i can transfer files between my tablet and my desktop?

I have tried 'FAT32' but Galaxy Tab can't read that format.

Thank you.
Have you tried FAT16? 

As far as I am aware, the standard format for all SD CARDS is FAT16, so it should work for tablets as well.

Also, could it be that the system that you use to connect your drive to your galaxy tab is broken?