Unable to Format DT100/4GB

Hello,
My Kingston Data Traveler 4Gb Pen Drive suddenly shows that it is Write Protected and I am unable to format it even at low level and also tried to edit the partition table with GUI based PTEDIT32.EXE, but I am not able to make any changes to the Drive even unable to rename it. I tried this on different PCs and Notebooks with no success. I did not submit it to service center as it contains sensitive data. Guidance and help would be appreciated.