I'm replacing an aging laptop whose casing is falling apart. Its Windows 7 installation is obsolete, although it still has a fairly capable i7-3610QM processor that I can't practically reuse. I also have a somewhat newer laptop, probably from around 2018, with an i3-8130U and 8 GB of DDR4 memory, but it is missing its hard drive. A Windows 10 desktop is available to help create installation media and transfer files.
I found an older hard drive that previously ran Windows Vista. It reports good health, but it will need to be erased and reformatted. I have installation copies of Windows 10 and the latest stable Ubuntu release, and I'm considering installing Windows first, leaving unallocated space for Ubuntu afterward. I've heard Rufus can be used to create bootable USB drives, but I'm inexperienced with this process.
What would be the safest order and method for installing both operating systems, and are there any compatibility, partitioning, or boot-mode settings I should know about before starting?
3 Answers
Dual booting should work fine on that laptop. Install Windows 10 first, then shrink the Windows partition from inside Windows to leave unallocated space. Install Ubuntu into that free space afterward; its installer should detect Windows and configure the boot menu automatically. Make sure you back up anything important first, since installing Windows on the old drive will erase it. Also check whether the laptop uses UEFI, and create the USB installer in the matching UEFI/GPT mode rather than mixing legacy BIOS and UEFI.
Using Rufus to make the Windows and Ubuntu USB installers is reasonable. Disconnect any other drives during installation if possible so the bootloader does not get written to the wrong disk. Install Windows first, confirm it boots normally, then boot the Ubuntu USB and choose the option to install alongside Windows or manually select the unallocated space. Keep the laptop plugged in, and remove the USB drive when each installer tells you to restart.
Since you don’t really need Windows beyond familiarity, another option is to install Linux as the main system and run Windows in a virtual machine with VirtualBox or VMware. That avoids many dual-boot problems and lets you test other operating systems without rebooting. The main limitation is that a virtual machine may not be suitable for demanding Windows games or hardware-heavy applications.

I don’t have much need for Windows except that it’s familiar, so I’ll probably try the virtual-machine approach first.