The PC immediately transitions into the BIOS setup.
The PC immediately transitions into the BIOS setup.
I recently assembled this system about a month ago with completely new components. After a month of use without any problems, my PC immediately enters BIOS. EZ mode doesn’t recognize any drives in the boot priority area, but when I switch to advanced settings and check the SATA and NVMe configurations, they are detected or displayed. I’m uncertain what to do next.
I attempted to reset the BIOS by removing and reinserting the CMOS battery, but the issue remained unchanged. I also tried connecting a USB drive with a Windows installation, which correctly reads the drives with accurate details. However, when trying to install Windows on an already installed drive, the system displays an error: “Windows cannot be installed on this disk. The selected disk has an MBR partition table. On EFI systems, windows can only be installed to GPT disks.” I’m not sure what this means, but I thought it might be useful to share. Updating the BIOS didn’t resolve the problem.
To clarify further, UEFI and Legacy BIOS represent two ways to initiate a computer. MBR and GPT are different boot disk formats, enabling practical operations once the system is running. (While technically UEFI and BIOS differ, many refer to UEFI as BIOS for simplicity, so I'll use UEFI and Legacy.) In essence, combining Legacy with MBR is outdated, whereas pairing UEFI with GPT is current. Your device likely was set up with Legacy + MBR, but now it's operating in UEFI mode, preventing booting from an MBR disk or installing Windows via MBR. It remains unclear whether the issue began with a switch to UEFI or if a CMOS adjustment caused problems initially.
As previously mentioned, you might attempt to access the Boot menu and turn on Compatibility Support Mode (CSM) before restarting, to test functionality. You may notice CSM is disabled. If so, this could indicate your motherboard attempts to use integrated graphics, possibly due to a GPU connection—both UEFI and GPT settings might be active. Adjust the Graphics settings, choosing Primary Display as Auto or PCIE, and turn off iGPU Multi Monitor.
If enabling CSM isn't possible, or it still fails to boot, and you're willing to reinstall Windows (which will erase data), you can convert your disk to GPT using guidance such as this: https://www.dell.com/support/kbdoc/en-uk...mbr-to-gpt
The issue occurred after a period of normal operation, with the device functioning well until it was turned off and not used for a short while. Then, when you attempted to restart it, it failed. There were no changes made during that time.
Unless it keeps happening, it's going to be down to being Just One Of Those Things. Glad it got sorted painlessly anyway!