It is estimated that there is something wrong with your Dell computer system. You can try to restore the factory settings.

The method is as follows: (1). Before booting into the system, press F8 to enter the advanced startup option of Windows 7 and select "Repair Computer". (2) Select the keyboard input method. (3) If there is an administrator password, you need to enter it; If no password is set, just "OK". (4) After entering the system recovery option, select "Dell DataSafe Restore and Emergency Backup". (5) Select "Select other system backups and more options", and then click "Next". (6) Select "Restore My Computer" and click "Next". (7) After selecting the correct factory image, click "Next" to start restoring the system to the factory state. Note that during the recovery process, the notebook needs to be connected with an adapter. When you are finished, just restart your computer.