This is a problem that occured today while I was working at my desktop computer. The monitor suddenly went from the usual display to a scramble of colours on the screen. I restarted it and have since restarted it and the same display of a scramble of colours fill the screen. I am unable to access any part of my desktop, cannot start in safe mode, or use any keyboard commands. If I turn my monitor on without the computer being turned on, the monitor test scrolls across the screen as per normal. I'm not sure what other information will be needed but this is a relatively old computer, has not had any such problems in the past, operates on windows 2000 and it is a CRT monitor.
Thank you in advance for the assistance, it is much appreciated and I hope this issue can be resolved.