Sandisk cruzer 16GB became read-only

I have had my Sandisk 16GB for some time myself and for some reason starting yesterday it also now will let me open the files, but I can not save anything to it as it says it is now read only.  I got to the file properties and they for the files on the drive and they show up as archived.  I change that and make sure the read only box is not checked and hit apply.  I exit out and come back and the properties are back to the same.  I can not save new files on it either.  I have Windows 7 Professional on this machine, I have not tried it on another PC, but will here shortly.  I also would love to know what I can do to resolve the issues.