安装Ubuntu后Windows无法启动，求助恢复Windows及实现双系统共存方案（附Boot-Repair信息）

Hey Thomas, sorry to hear about the mix-up with your son's laptop—no need to panic, we can sort this out together, and even turn it into a fun learning experience for him too! Let's start with getting Windows back up, then walk through how to set up a proper dual boot later.

第一步：尝试恢复Windows引导 #

Looking at your Boot-Repair log, the first thing to try is fixing Windows' native boot loader:

• Grab a Windows 10 installation USB (you can create one on another PC using Microsoft's Media Creation Tool)
• Boot from the USB, select your language, then click Repair your computer
• Navigate to Troubleshoot > Advanced options > Command Prompt
• Run these commands one by one (press Enter after each):
  • bootrec /fixmbr (Fixes the master boot record that tells your PC where to look for operating systems)
  • bootrec /fixboot (Repairs the boot sector of your Windows partition)
  • bootrec /scanos (Scans your drive for all installed Windows systems)
  • bootrec /rebuildbcd (Reconstructs the boot configuration file that lists your available OSes)
• After running these commands, restart your PC—if all goes well, Windows should boot up normally.

第二步：检查BIOS/UEFI设置（如果引导修复没用） #

Since your son mentioned changing BIOS/UEFI settings, let's double-check those:

• Restart your Dell laptop and press F2 (or sometimes Delete) to enter BIOS/UEFI setup
• Go to the Boot tab, and make sure Windows Boot Manager is at the top of the boot order list
• Check Secure Boot: If your son disabled it for Ubuntu, Windows might need it enabled to boot—toggle it on and try restarting
• Verify SATA Mode: Make sure it's set to the same option it was in when Windows was installed (usually AHCI; changing this can cause boot failures)

第三步：后续双系统安装指南（for you and your son） #

Once Windows is back up and running, setting up dual boot with Ubuntu is totally doable—here's a simple step-by-step:

• First, free up space on your Windows drive: Go to Settings > System > Storage > Disk Management, right-click your Windows partition, select Shrink Volume, and allocate at least 20GB (more if your son plans to install lots of apps) for Ubuntu
• Turn off Windows' Fast Startup: Go to Control Panel > Power Options > Choose what the power buttons do > Change settings that are currently unavailable, then uncheck "Turn on fast startup (recommended)"
• Create an Ubuntu 24.04 installation USB: Download the ISO from Ubuntu's official site, then use a tool like Rufus to write it to a USB drive
• Boot from the USB, select Install Ubuntu, follow the prompts until you reach the Installation Type screen
• Choose Install Ubuntu alongside Windows Boot Manager—the installer will automatically handle partitioning and set up the GRUB boot menu (which lets you pick Windows or Ubuntu when you start the PC)
• Finish the installation, restart, and you'll see the GRUB menu—pick the OS you want to use each time!

要不要从头重装？ #

If the boot repair steps don't work, a clean Windows reinstall is an option, but you'll lose any data on the Windows partition that isn't backed up. I'd recommend trying the boot repair and BIOS checks first—they have a good chance of fixing things without wiping anything.

备注：内容来源于stack exchange，提问作者Thomas Richter