Whenever you startup your Dell computer and suddenly the screen display a black DOS screen with a blinking cursor in the left hand side of the screen and after restarting the computer many times a message is being displayed Previous attempts at booting this system have failed at checkpoint [USBD]
and after a hour the computer will automatically load the windows

There are 2 steps you can do to fix the problem

you should adjust the USB setting in the BIOS and before performing the step disconnect all the USB devices and restart your system and wait till you see the Dell logo being displayed and start pressing the F2 key to enter the BIOS setup and press the down arrow key and search for the Integrated devices and press enter and a small dialogue box will be displayed after pressing the enter key which will list all your devices and again press the down arrow key which will highlight the USB emulation and the default setting is on and keep pressing the space bar key which will change the setting to No boot and press the escape key and the dialogue will be disappeared from the screen an again press the escape key and again the same dialogue box is being displayed and save all the changes an exit which is highlighted in blue an press the enter key the system will get automatically restarted and these are being made into BIOS and now

Reset the Dell Dimension desktop System Setup (BIOS) to factory defaults. And again you restart the system and when the Dell logo screen is displayed press the F2 key as soon as possible and as you enter the setup and press the ALT+F key and press the escape key and save the changes and press the escape key
Restart the system.
The Dell logo screen appears.
Press F2 to enter the System Setup (BIOS).
The System Setup screen appears and now the BIOS is set to default.