Write protected USB thumbdrive

This was a brand X bought on Ebay and shipped from China. Expecting it to work, I threw out the paperwork. Duh. So I don't know who made it and who to ask about the 'write-protect' that it came fitted with. No, there's absolutely no switch. I was able to format it in Disk Management, but it went back into WP mode half an hour later. So I formatted it three more times in a row, then started loading stuff on.
Then it stopped the load, because - you guessed it - the write-protect was back on.
Does anyone have any ideas?

 

There are all kinds of horror stories from purchasing USB drives from the net. I am looking for a tool to test the drive & found this one - not the one I've seen previously
http://www.raymond.cc/blog/archives/2008/03/21/how-to-check-and-test-usb-flash-drive/
but if I find it I'll post again.
Just wondering how big are the files & what format are you using? Fat32 or NTFS?

may help
http://reviews.ebay.com/How-to-chec...ke-USB-flash-drive_W0QQugidZ10000000003407025

 

Thanks, foogoo, for the fast reply. The drive is 16 gigabyte in FAT32, and from the mass of stuff I've been through on the net, it seems that write protect is executed as much by the item itself as by the host computer. I tried a number of confident registry fixes, none of which worked. So I wasn't really paying attention when I finally hit paydirt and came across something that actually worked. Or seems to work, so far. I'm dubious to celebrate because so often the write protection eventually reappears. But fingers crossed, it's looking pretty okay.
If I can find the steps, I'll post it as a final solution to what seems to be a horrible problem.