Turned on my dell the other day to discover that, the monitor doesnt display anything, it doesnt sound like its booting, and none of the USB ports are functioning!!! All help appreciated, thnks

If you do not get the usual single beep when you power up, that means the system is not 'running'. This is 'usually' caused by either a power supply or motherboard/CPU failure. However a device connected to the motherboard that is defective 'can' cause the motherboard to fail to operate correctly and cause the same symptom. One way to try and determine the defective unit is to disconnect all the drives and pull all the cards except the RAM and video card. If you still don't get a beep Remove the RAM and then try removing the video card. Still no beep, you have narrowed it down to the power supply, motherboard or CPU. Note that you should get error beeps for defective RAM or video cards, but there are times that you won't. However you normally don't need them installed to get the POST beep. If you get a beep And you get a monitor display, one of the devices that you disconnected could be the problem. If you get a beep and no display, you probably have a monitor or video adapter problem.

I have worked on several computers at the university. We have the same problem. The computer will turn on, the monitor will not display anything, and the keyboard and mouse (both usb) will not function. Although, we were getting beeps (check the manufacuter beep codes). the solution I have found was to reseat the ram. Take the RAM out of the slots, replace them, and boot up.