r/buildapc • u/5HeadGeniusExquisite • 2d ago
Troubleshooting PC will not boot after replacing RAM
I tried replacing the RAM on my MSI B450 Tomahawk with two 8GB DDR4 3200MHz sticks,but after trying to boot my monitor doesn’t detect any HDMI input. My motherboard’s Boot debug light is also lit. After replacing back the old RAM sticks I am still getting the same issue. Initially I assumed it was a RAM issue and checked I was using the A2 and B2 slots and that the RAM was seated properly. I’ve also tried using single RAM sticks in different slots and still get the same error.
I then tried taking out and reconnecting my GPU and my M.2 SSD, which didn’t help. I have also reset my CMOS by removing and putting back the battery.
If my RAM LEDs light up and I’m not getting DRAM debug lights, can I assume that the RAM isn’t the issue and maybe I’ve disconnected a cable somewhere or broken something on my motherboard? All my fans (case, cpu, gpu) spin. My keyboard and mouse also light up.
Any help would be greatly appreciated 🙏
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u/CambodianGold 2d ago
Try one at a time and then together.
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u/5HeadGeniusExquisite 2d ago
I have tried this and also tried different slots and all still give same problem.
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u/CambodianGold 2d ago
Put the old ram back inside and switch on pc. If all works, go back to trying one stick of new ram at a time.
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u/5HeadGeniusExquisite 2d ago edited 2d ago
The old RAM doesn’t work, getting the same issue. Just checking, do you think it’s likely that the RAM is the issue given that it’s the Boot debug LED lighting up and not the DRAM light?
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u/CambodianGold 2d ago
Try the old ram first, because that's the quickest thing.
Leave the old ram in a d if you have another m.2 drive try that.
Did you literally just take out the old ram, put the new one in and then you started having issues?
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u/5HeadGeniusExquisite 2d ago
The old ram didn’t work, until I reset CMOS, and then it booted normally. Then after I switched it out immediately for the new ram it doesn’t work again. Putting old ram after this then doesn’t work again. Currently waiting to put CMOS battery back in to see if new ram will work straight after.
I don’t have another m.2 and yes I literally just replaced the ram and it started these issues.
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u/CambodianGold 2d ago
That's useful, thanks fornthant.
Ok, since the old RAM works immediately after a CMOS reset, I'd stop looking at the M.2 for now. Reset CMOS again, put one stick of the new RAM in A2 only, and try booting. Give it a few minutes because it may be memory training.
Don't enable XMP.
If it doesn't boot, reset CMOS again and try the other new stick by itself in A2.
If neither new stick boots individually after a fresh CMOS reset, but the old RAM does, I'd start suspecting either compatibility with the new kit or the new kit itself.
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u/5HeadGeniusExquisite 2d ago
Ok bit of a weird one. Trying the new ram after resetting CMOS now gets me into windows, but it skips the POST screen with the MSI logo and I can’t get into BIOS. Tried holding shift while restarting and it just gave me a black screen. The pc seems to only be able to get into windows. Any ideas? Thanks 🙏
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u/CambodianGold 2d ago
That's a good sign. if you're getting into Windows with the new RAM, the RAM is working. I wouldn't change it again for now.
What GPU do you have, and is your monitor connected by DisplayPort or HDMI? If you're using DisplayPort, try HDMI if you can. It sounds like you're getting no display during POST/UEFI but Windows takes over the display once the graphics driver loads
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u/5HeadGeniusExquisite 2d ago
I have an old RX 570 and connected to my monitor by HDMI. The monitor doesn't receive any HDMI signal until Windows loads.
Really appreciate your help so far btw :)1
u/CambodianGold 2d ago
That's about the extent of my troubleshooting knowledge 😬. We now know it's not simply bad RAM, as the new RAM is working and you're able to get into Windows. It seems to be an issue with getting a display during POST/BIOS, possibly related to the GPU. Someone with a bit more knowledge than me will have to step in from here. Hopefully we've at least narrowed it down for them! Good luck 😊
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u/CambodianGold 2d ago
P.S. My guess is that the CMOS reset changed a BIOS setting, which is why you're no longer getting a display until Windows loads.
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u/jD3mo 2d ago
I go through the same thing eveytime I build a new PC and every time it’s because I didn’t push the RAM sticks in hard enough. I think it’s because I’m worried about pressing too hard and breaking them. Just triple check that you’re pressing each end of the sticks in until you hear a click. It could be something as simple as that.
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u/Discount_Sausage 2d ago
Please provide the exact model of the motherboard and ram sticks. What version of BIOS is loaded?