Delete protected files -- this is really challenging.

I accidentally downloaded some files into a folder on my workplace computer. I could not delete them because the files in this folder are protected. I learned that I do not have the previledge to delete files from this folder. Any way to delete these files? I have tried the following methods but obviously they did not work.

I tried to restart computer in safe mode. It did not allow me to log in this this mode.

I tried to delete them under DOS, still I could not delete these files.

I tried to boot a computer from CD (Bart's XP), the computer showed a blue screen.

I tried a program " unlocker", it will not even run on this computer.

Please do not tell me that I have to confess to my supervisor. This is my last step. hehehe...