This can be a simple problem that generally happens with everyone's PCs.
Just open the cabinet, remove the CMOS Battery and RAM. Keep it idle for around 1-2 minutes. Meanwhile clear the dust accumulated over the motherboard. Now insert the RAM in to its slot and the battery too.
Startup the computer. If the display comes, then everything is ok. Change the system time; save and exit.
Everything should go fine by now.
Else try replacing the RAM with another.