I have an IC7-G Max3.
Do the following.
Undo everything from the motherboard. I mean everything. Cables, HD's ,CD-Roms, cpu, memory you get the picture.
Typically when a system doesn't boot, a single component isn't seated properly.
1. Install cpu
2. Install memory <<<< seat it make sure
3. Attach the power supply cable
4. Attach the 4 prong P4 power cable
5. Insert video card.
6. Attach keyboard
7. Attach monitor cable
8. Attach power cord to case
Ok what you have now is the absolute bare equipment to boot.
Turn on your machine and see if it can boot to BIOS.
If it doesn't, try clearing the cmos. Unplug the case, move jumper to 2,3 hit the power button, even though the system doesn't have power the capacitors retain a charge until you do this. Most systems will clear without doing this, but some don't. It's a good habit.
Rejumper to 1,2 , plug the power cord back in and try again.
If the system doesn't boot now, you have a problem with one of the components.