text: The reason why the yahoo file cannot be deleted is because is being used by a program. the only way to delete that file,is if you end the program. try restarting the computer and going into safe mode.  To do that, while your computer is just beginning to boot up, press the F8 key until you see a menu pop up. Select "safe mode" from the menu and press enter.  Once you're at the welcome screen, choose administrator.  Once you're there, click start->search and type in the file you want to remove. WARNING: this action might make some things not work.