Won't book, won't post

Hi. I have problems
I came to my pc today, and it wouldn't boot. After numerous attempts, and failure to enter the BIOS, I was shown the refresh/repair /reset page.
I tried refresh, that did not resolve the issue.
After a few more attempts to boot, I got that choice screen again (don't know how to bring it up myself) .
This time I tried repair, that process took some time, but failed.
I was also given a restore choice. I tried that, and it should have restored me to before I installed Lightroom. That didn't work either.
Now I can't boot, the BIOS screen doesn't even display 90% of the time, and when it does I cannot enter it.

I'm totally stuck, help!

Hi. When the splash screen comes up, which is every few times it attempts to boot, I press delete, f12, end.
These are all keys which should get me into the BIOS, but they don't. The machine just powers off, and tries again.
I have a Gigabyte motherboard, which has a dual BIOS (?). The machine sometimes makes it to this dual BIOS uefi page, but powers off almost immediately. The screen is blank apart from the header.
Everything was fine earlier.
What do you suggest? I was going to try fresh install of W10 or W7 HP, but this is impossible without the BIOS.

Hi there
Open up the machine and disconnect ALL the HDD's and then see if you can get into the BIOS.

Note -- the CMOS battery might also have gone - change that if it's defective.

You can also remove all the memory sticks -- just keep keyboard and monitor connected -- even with 0K RAM connected - i.e all the memory removed you should still be able to see the BIOS POST screen.

Then start replacing the memory modules and re-connect the HDD's (one at a time and see if you still get into the BIOS).

There might be a "recover BIOS or use Alternate" option in the machine -- I can't say I've ever sees a mobo with TWO bioses's. !! Your mobo documentation should tell you how to "flip" the primary BIOs or recover it.

Cheers
jimbo

Hi, thanks to you both for your input.
I've tried cleaning the cooling fan assembly, and also disconnecting beds and RAM, in various combinations
No difference I'm afraid. In fact I've made the situation worse somehow.
There is no longer any attempt to post. Nothing happens on screen. When I try to start, the PSU starts, the case fans, and cooler all start, and then stop almost immediately.
I thought the PSU had failed, but I had replaced the front switch headers incorrectly. They are now on the right pins but no post
So, I'm not getting anywhere near the BIOS, whereas I was getting the splash screen before.
This is turning into a disaster :-(

Hi. I've replaced the cmos battery.
This gave me a brief hope, as it now tries to post for longer. Everything starts, fans etc.
Still nothing on screen though, so I'm nowhere near the BIOS :-(

Have you got an install disc? if so insert, then click on computer repair, open command prompt and type.
bootrec /rebuild then reboot computer.
If you do not have an install disc you can get the advanced menu by doing the following,
Start computer, then holding down the shift key restart the computer.