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1 Rookie
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2 Posts
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46
September 25th, 2025 21:01
Dell t5810 not posting after enabling secure boot and disabling legacy ROM
So my Dell Precision tower 5810 wouldn't display. I finally got a vga cable, hooked it up to my gpu and got post. Then it wouldn't boot into windows, so I went into the BIOS and switched from legacy to UEFI, restarted the comp and still wouldn't boot into windows. So I went back into the BIOS and enabled secure boot, and disabled legacy ROM. Completely forgetting that I don't have my newer gpu anymore. I'm running an older gpu now that needs legacy ROM to actually initiate on startup. I have no idea how to turn legacy ROM back on again with no post. I already tried resetting the VRAM to no avail. I tried restoring the BIOS with a FAT32 USB and my latest BIOS update to no avail. I re-seated literally everything on the mother board, nothing. Any advice would be greatly appreciated.
My only next step is to either, 1, get a new gpu, or 2, borrow a gpu just to revert back to the original settings. But before that, I would really rather find an alternative solution
Thank you in advance
anne_droid
3 Apprentice
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1.2K Posts
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September 26th, 2025 08:45
Hi
Try another OS like Linux Mint which will run LIVE and doesn't need a HDD/SSD/Nvme to be installed.
It will boot and offer a "Low Res" option probably.
This then shows if it is a "Windows" problem, or a BIOS issue.
Then you consider whether you go for Legacy MBR or GPT/uEFI with or without Secure Boot.
Because you current storage device may need converting to suit the BIOS options chosen.
If in doubt please ask.
bradthetechnut
7 Technologist
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9.1K Posts
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September 27th, 2025 23:40
The 5810 goes back to 2014. Tip: Change or test the size 2032 motherboard battery. Bad batteries affect BIOS and therefore PC operation. Bizarre problems depend on the model. It might be wise to also do a BIOS reset via the blue jumper method. Note any special settings first, but see if it boots with just the reset.
Changing some settings in BIOS can cause Windows to not boot. Windows typically needs to have the same settings as it was loaded in. Ideally, it should be loaded with Secure Boot on, UEFI, and AHCI for non-RAID setup, otherwise RAID if there's a RAID setup. RAID is typically the default setting for servers/workstations, even if it only has one SSD/HDD. Legacy ROM off. See how it behaves after changing the battery. May be there isn't a need to reload Windows.
(edited)