My USB Mouse shows the cursor moving on the screen but cannot click on anything and USB Keyboard does not work.
@newcomer, hit start then control panel then mouse. Then after that Keyboard. You should have two pieces of hardware available.
1, The Synaptics mouse pad and Standard Microsoft keyboard that came as part of your Dell System.
Setting B (the USB alternative)
2. The aftermarket USB mouse and Keyboard that you are trying to make functional.
Make certain that you have the correct item checked as the one to use.
Then go to the properties portion of that device and set up the options of the mouse and keyboard.
3. If the new usb mouse came with installation software, Install it so the new device and drivers are available to the system.
Should be one of the three. Give em a go and let us know