# POST black screen, error B2



## hirobo2

I accidentally pulled out a USB HDD during POST.  Now, my computer won't boot up past POST.  It displays a black screen with an error message "B2" at the bottom right.   I can't access the BIOS by press [Del] either.  I'm guessing my pulling out the USB HDD must have short-circuited the BIOS during the POST sequence.

What can I do short of replacing the mobo?  (It's an MSI B75A-G43 with on-board graphics only).  Will I need thermal paste if I'm to replace the mobo?


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## Darren

Reset CMOS by pulling out the CMOS battery on the motherboard. Leave it out for 5 minutes or so then reinsert and try to reboot.


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## hirobo2

^ Tried that.   It didn't work.  Was I supposed to disconnect the power too?  (All I did was turn off the switch at back of PSU).  

Anyways, will I need thermal paste when I transfer the CPU to a new mobo?


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## Darren

Definitely want to disconnect the power supply...


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## Agent Smith

Yes, turn off the PSU in the back. Now press and hold the power button for the computer, then pull the CMOS battery. Should be a good five to ten minutes. I have heard of CMOS chips being replaced as well. I have no idea if your board can do this and how to get BIOS in the chip if the BIOS isn't in the chip. Does your board not have dual BIOS? If it does flip the switch on the motherboard to BIOS 2 or what ever it's called. Could say CMOS 2.



hirobo2 said:


> Anyways, will I need thermal paste when I transfer the CPU to a new mobo?



Yes. And you don't need Arctic Silver or any of that fancy stuff either. The Temp difference between that and generic is like 2-3 degrees.

If you transfer the CPU, make damn sure the MOBO and the BIOS can support it prior to replacing. If the MOBO BIOS doesn't support that CPU, it would be wise to flash to the latest BIOS prior to CPU replacement. My Bro made that mistake. LOL And I freaking told him too!


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## hirobo2

So help me, I've never built my computer b4 and don't know much about mobos and sockets.

This is the mobo I currently have that is giving me the black screen:

http://msi.com/product/motherboard/B75A-G43.html#hero-specification

Is this a viable replacement (the above mobo has Intel HD4000 graphics and the CPU is a core i5 Ivy Bridge):

http://www.ebay.ca/itm/ASUS-P8H77-M...313628?hash=item35f1578d9c:g:5WMAAOSwuTxV8E9~

and will it fit into the same case, which is a tower desktop?


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## johnb35

What exact processor do you have?


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## hirobo2

I don't know.  All the manual said was Intel Core I5.  I do know that it's a quad core Ivy Bridge...


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## johnb35

Well, need to know exact processor as some motherboards only support certain processors.  Is it installed in a system that is currently working or no?  If not, then you could give us the numbers that are listed on the processor to verify which one you have.


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## hirobo2

I don't have a working system to look up its ID.  Bought it when Ivy Bridges were just coming out and 3D 22nm was the hot new thing.  Most mobos should support these CPU's, right?


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## johnb35

As I said, would need to know exact one.  Some motherboard only support certain processors. Just post the numbers are on top of the processor so we can look.


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## hirobo2

I would need to reopen the case, but wouldn't the heat sink block the numbers?

Anyways, from the MSI website, it's got to be one of these Core I5 Ivy Bridges:

i5-3550
i5-3570T
i5-3450S
i5-3550S
i5-3450
i5-3570K
i5-3475S
i5-3470T
i5-3330
i5-3330S
i5-3570
i5-3470
i5-3570S
i5-3470S
i5-3350P
i5-3340S
i5-3340

But, I couldn't find any specific CPU numbers on the ASUS website:

https://www.asus.com/Motherboards/P8H77M/specifications/

The thing that worries me is they each use different chipsets, or is this a non-issue?


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## johnb35

Yes, you would have to remove the heatsink. 

Here is the cpu support for the asus board.

https://www.asus.com/Motherboards/P8H77M/HelpDesk_CPU/


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## hirobo2

Btw, while we're at it, can I use a micro-ATX board inside a case that was designed for full ATX?


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## johnb35

As long as the case supports it.  What exact case do you have?


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## hirobo2

It's just some generic mid-tower case with the word "blade" on it with a logo that looks like a ninja-star...


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## johnb35

Originally you said full atx, now you are saying a midtower.  Which is it?  Midtower's will accept a micro atx board.


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## StrangleHold

Don't really see a USB hard drive being unplugged booting or in windows really hurting the board. If it was accessing the drive I could see it getting Data corruption. Seems like something else going on.


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## hirobo2

^ I once killed a laptop by furiously typing the keyboard at the POST screen right after a BIOS update.  I'm guessing the BIOS is the most vulnerable during the POST sequence...


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## StrangleHold

Unplug it. Push the power button a few times. Reset the bios by the jumper or take the battery out. With it out or the jumper set, press the power button a few more times. But the jumper back or the battery. Plug it back up and see if you can boot or at least get into the bios.


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## hirobo2

Now wait a minute on the MSI mobo's web page:

http://msi.com/product/motherboard/B75A-G43.html#hero-overview



> M-Flash
> 
> Compared to common motherboard which need extra BIOS chips, MSI’s M-Flash has a double advantage which doesn’t need extra components and secondly, all your BIOS data will be saved in *the USB drive*. The stored data does not only have backup and upgrade function, moreover *it can also be seen as a portable BIOS chip* which is actually able to boot up your PC.
> 
> Features
> - Backup/Restore Your BIOS to/from Any USB Flash Disk
> - Avoid Unnecessary Repair Due to Accident Failures During The Upgrading Process
> - Earn more BIOS Lifespan by Reducing Unnecessary Rewriting Process



Has anyone tried it, using a USB flash drive as a BIOS replacement?  Is there a remote chance I could rescue the mobo by using a pen drive as an alternate BIOS chip?  Will the system even attempt to load the BIOS from the USB drive in such a state?

It seems my problem could be solved if I could reflash the BIOS...


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## johnb35

hirobo2 said:


> Has anyone tried it, using a USB flash drive as a BIOS replacement? Is there a remote chance I could rescue the mobo by using a pen drive as an alternate BIOS chip? Will the system even attempt to load the BIOS from the USB drive in such a state?



Unfortunately, you would have had to make a backup of the bios beforehand.


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## hirobo2

This guy had a bad flash.  I'm assuming he didn't make a BIOS backup before doing the flash.  Claims he dled something from MSI and was able to reflash it.  How did he do it?

http://www.tomshardware.com/forum/id-1708959/msi-z87-g45-bios-recovery.html


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## johnb35

Depends on how bad the bios is.  Looks like his was set to boot to usb first.


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## hirobo2

OMG this is retarded.  After much digging within the MSI forum, I got my mobo working again.  It seems a lot of ppl had the black screen when they did a BIOS update.  *The solution for MSI mobos* is as follows:

1.  Unplug all cables connecting to the mobo except the power cable from the PSU.
2.  *Move memory modules to DIMM3 and DIMM4*.  (_This was the step that made all the difference for me_, the factory installed my memories at DIMM1 and DIMM3.  This move somehow breaks the loop that causes the BIOS to display a black screen on every boot).
3.  Reset CMOS either by jumper or pulling out CMOS battery.

Voila, my BIOS is back to default settings and my PC works again!

And btw, I wouldn't reflash the BIOS.  The BIOS isn't like a regular OS update.  It isn't something you mess with unless you absolutely have to...


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## Agent Smith

Now that you sorted that out you should back your BIOS up. LOL


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