Error comes in saving the file

Can anybody tell me how I can save my photoshop file? When I want to save my file this error “Cannot save file because it was left open or is being modified” comes everytime. I am overwriting a file and using Photoshop7.0. :confused:

Maybe that file it is opened also by other aplication in the operating system.
Try save it with other name (Save As), or in other folder.

the images it already open you cant save it until you sure you close it, sometimes you need to restart to be able to reset the cashe