How format a write protected USB drive with a blocked file

I have this problem: I can't format my USB drive because I get the message that it is write protected. I also have a blocked file on the drive which causes the drive to be write protected (I think). The file system is NTFS. The usb drive is an Intenso 16GB.
Here's what i've tried:

- regular formatting
- formatting using HP usb format tool
- Checked under properties to see whether the read-only box might be checked. It wasn't
- deleting the stream of the blocked file with an alternate data stream viewer.
- searched for a switch that could've caused my usb to be write protected. Didn't find it.
- I checked these programs out: lockhunter, unlocker, eraser. None of them worked.


Is there anyone who could help me?

Thanks