The Windows 10 system displays a dual-boot setup with only Windows 7 available.
The Windows 10 system displays a dual-boot setup with only Windows 7 available.
I cleaned out a lot of dust from my Windows 10 64 bit PC. I left the power cord in but only connected one hard drive—its files are there, but no operating system is installed. After reinserting it into the motherboard, I think I might have put it in the wrong slot. Once I turned it back on, the Advanced Boot Menu appeared, offering two choices: Windows 7 or Windows 7. Selecting either option failed, prompting a request to insert a repair disc. I tried connecting it to any available SATA port and rebooting, but the process still worked. I also attempted to launch BIOS and set the 1TB HDD as the first to load, yet it continued. Note: My motherboard is an ASUS Sabertooth 990FX R2.0 with five HDDs installed; it’s a custom build, not a standard system.
It seems the system might be running Windows 7 with an upgrade to Windows 10, causing the boot menu to display as if it's still using Windows 7. There are a couple of boot options available: one resembles Bitdefender Rescue Mode, while the other appears to be a standard boot.
I upgraded from Windows 7 during the free Windows 10 upgrade period. It seems Bitdefender was installed then but I removed it afterward, which might explain its presence now. This is my first time seeing this in a long while. How can I restart normally into Windows 10 and fix the Boot Manager?
Adjusting the disk around likely altered which disk is being used during boot in your BIOS. Check your settings to confirm the right startup drive is chosen. The storage you have for data might still contain a Windows boot partition of roughly 500MB, and your system is attempting to start from that first.
You could attempt to start with just the boot drive connected to the computer. If you manage to boot, consider downloading EasyBCD—it's a utility I previously used for handling complex boot managers during dual-booting Windows 7 and Windows 10. It looks like your motherboard might still be running in legacy BIOS mode. There seems to be some confusion about whether UEFI supports advanced boot management anymore.
I attempted to unplug and only started with one hard drive each. One drive showed up with a Windows 7 dual boot prompt, another warned about BIOS limitations and guided me through enabling the boot device. I clicked OK, navigated to Advanced > Boot > CSM Parameters, and adjusted the settings to activate the boot device. Pictures were attached showing the interface I saw. I also changed the boot device order on my PC, which again triggered the dual boot screen (same image provided).
You need to connect both hard drives simultaneously for Windows 10 to launch. Your 1TB drive and the WD drive (size required) must be inserted into the designated SATA slots on your motherboard. After restarting the PC, Windows 10 should boot again, and you can test by connecting the drives to the brown SATA ports and trying to open easyBCD. If it still only shows one option, it might indicate a persistent issue with the installation or driver setup.