I have a pendrive(512 MB),I can't able to delete one file also copy new file to pen drive.
It shows write protected
Kindly give me your ideas
Thanks
Arun.

What's your pen drive model and version?
Usually there's a write protect switch on pen drives.. try to look for it.
Is it detected in your PC?

There are different models of pendrives, some that don't work on sortion Operating systems which makes them writer protected. With windows Xp there a plug and play systems which just installs most pen drives and enables them to be used on Xp. Do what Carlo said and which is also check for a Write protection Switch, some drives have them.
If using Windows 95/98 you will need to install Drivers for your model of pendrive.

If this Helps rate it

I also have the same problem. It is 256 MB pendrive. I have tried those things that are posted earlier here. But it doesn't work. It is for usb port 2.0; has the logo ball; and it has the no-575641165595 written in the pendrive ( I don't know whether this no would be of any importance). I use windows XP. Please help me.