protected - Write to SDHC card fails

I am using a Sandisk 8 GB micro SDHC card on my MileStone. The card is detected and mounted. I can read data from the SD card, but cannot write to it. There is no error when I attempt to write to the card.

It appears as if it's working fine, but after unmount and re-mount, the data written is gone. Even if I format it, it will restore to the previous state.

At last, I tried to format it, but the operation system formatting utilities were not working, it says

Windows was unable to complete the format

Then I use the "SD Formatter 3.0 Beta" from "http://www.sdcard.org/consumers/formatter_3/", and it says

The nemory card is write-protected. Please release the write protect switch."

but I can't find any switch on my micro SDHC card or SD card reader.

I see some useful information on that web site. It says

The SD/SDHC/SDXC cards have a "protected area" on the card for the SD security function. The SD formatter does not format the "protected area". Please use the appropriate application software or SD host device which provides SD security function to format the "protected area" in the card."

I think my card may be wholly protected. How can I format it?