After a power cut my PC is now not booting. Its hang, and no display on monitor is coming up. No beep?

The only thing i can suggest is to pull your CMOS battery out. Which located inside of the pc. Usally in the lower left corner of the motherboard. Leave it out for about 10 minutes. Unplug your computer then turn it on for a few seconds to get any remaining power out of it. Put the battery back in after 10 minutes then plug it back in. Power up and see if it has reset itself.