kaly99, Press CNTRL+ALT+DEL and click the task manager tab. Highlight the running task and click end task to see if that will remove the white box. If it is loading at startup go to start-run and type in msconfig. Once that opens choose startup task. Remove the checkmark from the programs that are running at startup. You may need to do one or 2 at a time to figure out which program is causing the white box.  
I have a dell inspiron N4010, and I recently encountered a problem when I start the windows 7 home premium, after the laptop have the home page,few minutes later this white box shows ups on the screen. Please any one with the same problem out there. Can any one help me, thanks.
white box on the middle of the screen