How to fix usb drive?

I have problems with TS8GJF500 (http://us.transcend-info.com/Products/No-274)- it becomes write protected in the process of writing to it on Windows 7. I'd used it for installation of Trisquel 7. I assume that I messed it up making it live usb many times. Then tried to fix it with fsck instead of fsck.fat, changing starting sector or sth. like that, hah.

So after little research I used dd zero bs=4M for complete data erasure. Then format it in FAT32 with gparted and again with disks (tried with disks at first to get an error; only gparted is not enough). Doing that procedure before using it on Windows 8 was enough to copy 1GB file without a problem. But back on Win 7 it's the old story. Today formatting it gave input/output error. Is it even fixable? If so could you give me the clear simple steps how to clean it entirely and format it properly. Obviously I'm doing it wrong now. Sorry for the messy info. I forgot all the things I've done to the drive and I get the feeling that new errors appear all the time.

P.S. I attach the details from today's attempt with gparted (leaving 50MB before and after the partition). And that is from disks (partition spanning the whole drive):

Error erasing device: Error writing 1048576 bytes to /dev/sdb1: Input/output error (udisks-error-quark, 0)