At the very least you should see the BIOS POST reports before Windows begins to load. POST stands for Power On Self Test and this is the BIOS checking the hardware and displaying messages on the monitor screen about the hardware on the system before Windows begins to load.
If you are getting nothing at all, no display at all on the monitor, then it looks like the machine is toast.
Time for a repair or a new computer I think.
I turn on my computer. The front panel switch lights up then quickly goes out. Fans are running, CD/DVD drive starts up. This happened after AVG system scan. Nothing on monitor.