Help! No mobo lights and blank screen after bios

[Stevul]

Hi, I have re-assembled my small form factor pc and can get into the bios ok but when I exit bios it does not boot up to windows and there are now no motherboard lights on the back of my pc. This is a 4-monitor setup but not for gaming:

i5-4460
Gigabyte GA-H81M-S2V mobo
8GB DDR3 Ram
Asus GT-710 Passive Graphics card for the extra 2 video outputs
120GB Patriot Blast SSD

The lights on the graphics card and the pcie x 1 wifi card do not come on but when in bios the bios screen appears on a monitor connected to the graphics card and on a monitor connected to the mobo. In bois the SSD is detected on the SATA port but when I exit bios it does not boot and I get a blank screen. PC fans work.

Could my motherboard be blown or partially blown?

Thanks

 

[DRagor]

If you can get to BIOS, your mobo is most likely ok. Either some BIOS settings are incorrect, or Win going stupid cos the hardware changes. Quick solution: try booting with just one monitor. If that won't help, more info will be needed. Like what Win you have, what hardware changes has been made.

 

[Stevul]

Thanks for the reply DRagor. It is Windows 7 Pro 64-bit downgraded from Windows 10 Pro. Have tried booting with just one monitor connected to the VGA on the Motherboard but did not work. I removed the motherboard as 'practise' because have ordered a Noctua CPU cooler (Stock cooler too noisy) which requires access to the back of the mobo. Have now put everything back in place except the graphics card and the wifi card and have this problem. I have just tried 'Boot Overide' in the bios and got the message 'Invalid signature detected. Check Secure Boot Policy in Setup'.

 

[DRagor]

So the only new hardware thing is cooler? That should not affect booting system in any way.
Are you sure you connected everything back IN THE SAME place? SSD connected to exactly the same SATA slot as before?
As for that message, check this: https://www.youtube.com/watch?v=l5k3ZhO826Q or this https://answers.microsoft.com/en-us/windows/forum/windows_8-update/security-boot-violation-invalid-signature-detected/18b49777-32d4-4918-87be-3291495e60d1 all it takes is to make some changes in BIOS.

 

[Stevul]

Great! Thanks DRagor! Disabling the Secure Boot in the bios has worked. Bios settings were reset to default after I reconnected everything to the motherboard.

 

[DRagor]

No problem, happy to help.