Do you hear any booting sound?
For self check you can do these steps:
1. Take out RAM Stick and clean the dust.
2. Clean the Mother Board also by using Blower.
3. If you have knowledge about How to install CPU. please clean the dust also of CPU.
4. Try to check graphic CARD if you have PCI CARD.
I just finished putting together my computer.
Hooked Monitor up to the motherboard and powered up.
Monitor directly goes into sleep mode.
Tried another, older, monitor.
Fans running lights going, CD Drive working, everything is powered up but nothing on the screen.
Any Ideas? any additional information you need from me i can provide thank you.