My Motherboard has a Big Problem

Hey !
I'm new in Tom's Hardware's website !
I have a disaster ... I don't know , my MoBo doesn't have any label written on it , I don't know it's name !
This is a home built pc. It's builder is gone right now !
The PC works great but I wanted to flash the BIOS ( from within Windows ( I'm Running Win 8 already ) ). The BIOS is an AMI BIOS , the motherboard is "To Be Filled By OEM" ( from within Windows when I run DXDIAG or CPU-Z )
But in the BIOS it's written. :
Intel G31 Date 28/08/2012 - It's not UEFI BIOS -

So ...

When I flashed the BIOS ( Not sure about the MoBo manufacturer , I used "Save" button in the "AMI BIOS Flash Utility" as a .ROM file ... Then i changed logo , and i flashed it ...
Okay ! ( I translated the whole of the BIOS Utilty Controles to French )

and ...

After the flash ... Restarted the PC !
And the Monitor entered "Power Saving mode" , the PC does POST , but nothing is shown in the screen !

As I mentioned before , I used "SAVE" button to save the whole BIOS configuration to a ROM file.

So , I think Flashing from within Windows is like shit ! But I'm not sure , maybe the discrete GPU is bricked ! Because I haven't made the MoBo boots directly from IGD !

My Motherboard as u know , is XXX ( Unnamed ) so don't say << this MoBo might have an integrated recovery option >>
And ...
The MoBo doesn make any sound ! Even though I remove the CPU , the VGA , the RAM ...

Holy Shit ... Ummm , it's like death !
Please don't say << Buy a new MoBo >> Or << Change the Chip >> I love complexity and I think u can help !

These hints may help u :
- Intel G31
- No Manufacturer name written in the MOBO
- NVIDIA Descrete GPU

That's what I ve done exactly

- BIOS flashed
- ROM file created by the AMI BIOS flashing utility and "SAVED" as a new file
- Making OEM logo ( Unknown Brand )
- Translating from English to French

Okay , So the whole reason why i ve done the flash :

- When Inserting USB Drive , the BIOS / the system won't recognize it
- I managed to buy a new 1 TB HDD but the BIOS doesn't support it !

I haven't upgraded the BIOS to a new version tho. ! I ve just Saved the MoBo's BIOS status to a file !
I flashed from within Windows 8 - 9200 .

This disaster s created at : 28/09/2015 in my PC !

Note : I can't afford to buy new components !
I need this PC , I don wanna buy a new one instead !

Thank u for ur attention guys ! Hope u understand my "poor" language !

I hope u fix it for me ! My problem is unsorted , but anyone can take a look at it when needed !

Thank You a Lot for ur patience