New pc case and mobo p5b-vm do green light on board

Check your connections. Make sure the 24 pin is completely seated in the correct orientation. If you feel the slot, one side will have a slight ridge. The plug has a retaining clip on one side. The clip goes over the ridge on the plug, just to make sure it is oriented correctly. All the plugs have to be absolutely completely seated. The same with the ATX 4/8 Pin connection usually above the CPU as well as the power connections that go to the Graphics card.

Typically with most motherboard lights, green is good. An error will be a red light. Most boards have a green light that will be on just to show the computer has standby power. Also if your PSU is modular, make sure the plugs going into the PSU are fully seated.

The standoffs that Derekimo showed you screw into the case and have to align exactly with the screw holes in the motherboard. The motherboard screws into the standoffs (gold screws as you say). Make sure there are no extra standoffs. There should be 1 that lines up exactly with each hole in the motherboard, but there can be no extra standoffs.

derekimo said:

I think it's almost impossible to see anything like that, you got a pretty crowded case.

I know I would just probably pull it all out and start over, check things as I go to make sure.

Maybe someone else has some suggestions you can try.

Is this your case?

Rosewill FBM-01 Dual Fans MicroATX Mini Tower Computer Case-Newegg.com

Just posting it for others in case they want to know.

Derekimo is correct. A top mounted PSU is very difficult to wire neatly. You just have to find somewhere to hide the wires not being used and route the wires you are using some way to make them more orderly and neat. This is important. First, we can't see what is connected and what isn't. Plus, you have to allow for proper airflow through the case. As th wires are right now, there is no way you could get any airflow through the case. Heat is the biggest killer of computer components. Proper airflow is a must. Any unused hole in the case, such as the top 5.25" bays can be used to put unused wires. You have wires on top of the CPU cooler,which will make it difficult for the fan to turn plus it has to draw air from somewhere to cool your CPU. Organize the rest of the wires to run through the same general part of the case where possible. Tie them together with wire ties.

Remember, wire ties are your friend and they are very cheap. Use a lot of them. Tie wires together and tie them out of the way and to the case somewhere. If you have access holes and space between the motherboard tray and the back panel, it is good to run them between the motherboard and the back panel of the case. I don't know if your case has that. Again, top mounted Power supplies are difficult, but this will give you and idea of what you are looking to do.

If you disconnect the sata and power cables to the CD drive and all hard drives, it should boot, and allow you to go into BIOS. Set bios to optimized defaults, usually F5 save and exit. See if that works. If it does, connect 1 hard drive at a time and try to boot. The computer should POST with no hard drives connected.

If you get into BIOS, it will tell you the BIOS version you have, let us know what it is. It will also tell you what the values are for your +12V, +5V and +3.3V. Tell us what those are too.