Sandisk cruzer 4gb thumb drive gives error disk is write protected..Pl

You can do two things, first of all scan the drive for viruses. Some viruses have been known to cause a drive to be write protected and can make it a pain to access your files. If that doesnt work you can format your stick by going in to "My Computer" finding the thumb drive, right clicking and clicking the format option. If it wont allow you to do that, I really dont know what to do.