monitor no display light blinking

Solution
It just happens sometimes with a slight movement of the case. It also happens with the heating and cooling cycles over time. It is always one of the most basic things to do/check.
What have you tried so far?
Is your monitor plugged into the motherboard's video port or do you have an add-in card plugged into one of the PCI slots?

First thing would be to try that monitor on another computer/laptop.
2nd would be to try another known working monitor on your current system to rule out a bad monitor.