Windows boot up and monitor displays "no hdmi signal"

Hello,

If I turn on my computer after few hours turned off, the Windows boot up while the monitor displays "no hdmi signal". I've to keep it on until five minutes, turn off, turn on and it works fine.

I've tried the following:

- Undone overclock of CPU and GPU. The problem may have started the same month I've started playing with OC! However I didn't let they frying.
- Clear de RAM connector.
- Replace the RAM sticks.
- Use the other two slots and also use a single slot.
- Try to clear the slots with isopropyl alcohol and remove the mobo dust.
- Reinstall CPU. Thermal paste replaced.
- Reset the CMOS. Three methods used (jumper, pop out and BIOS)
- Replaced CMOS batery.
- Clear the graphic card connector.
- Boot using IGP. Setting IGP > PCIE changed in BIOS.
- Replace hdmi cable.
- Use second hdmi port of monitor.
- Check monitor mirroring a tablet with micro hdmi.
- Unplug power cord and hold power button for one minute.
- Look for stuffed capacitors (no experience).
- Put under Sun and use silica gel to remove moisture (fans had water)

Is there anything else I shall try?