Should I Reload OS on Used Laptop?

I just about agree.

Personally, I'd make a system image of the thing as it stands so I could get back to square one if it all went wrong.

I suggest you leave things as they are at first so you can go online and let it activate.
You can check its activation status at Settings, Update, Activation.
And you can avoid hanging around too long by using this - Force online activation attempt - NavyLCDR post #14 - ElevenForum
And do check that it's activated with a digital licence so you know you can reinstall without needing any product key.

- You can then run a Defender Quick scan to make sure there's no malware onboard that might try to sneak around during the clean install [not that I know how they might do so].
- - A Defender Full scan is not necessary. It takes ages but is not any better than a Quick scan. A Full scan is only useful when cleaning up after a malware attack has been removed.
- - How to Scan with Windows Defender - TenForumsTutorials
- You could also run a Defender "Offline scan" to check for specific types of hard-to-detect malware.
- - Windows Defender Offline Scan - TenForumsTutorials

- A clean install includes wiping the OS disk anyway so you don't need to do it separately. Clean Install - TenForumsTutorials
- Before doing it, consider Backup and Restore Device Drivers - TenForumsTutorials It will save you a lot of work afterwards.


All the best,
Denis

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mridzon said:

I'm buying a used laptop on eBay. It's advertised as fully functional with a fresh copy of Win10 Pro. My gut tells me I should retrieve the Win10 product key, wipe out the SSD, and reload windows, as a safeguard against any virus/malware/phishing software hidden in the OS. Would this be a smart idea, or can I just roll the dice and leave the OS as is?

I generally buy my laptops as used machines. Yes, normally the first thing I'll do is a clean install (well, maybe the second, after making a system image of it 'as delivered').

The installed key may well be the generic W10 Pro key VK7JG-NPHTM-C97JM-9MPGT-3V66T, if so it's not going to activate Windows on its own.

Check in Update & security > Activation. If it says there that 'Windows is activated with a digital license...." then you won't need a key to activate a clean install. You can skip entering a key if asked. Windows will activate from the existing digital license as soon as it can contact Microsoft's activation servers.

And do post back if any issues arise when doing the job.


All the best,
And thanks for the rep,
Denis

As it is a used computer you don't know what was installed with the previous owner. It can have a malware, a spyware or only a lot of garbage.
I would do a full Reset or even better, a Clean Install.
Before you do a clean install, backup all the drivers
Backup and Restore Device Drivers in Windows 10

A System image (drive image) is a kind of a zip file of your entire drive (all partitions) and it is saved on another drive (normally an external drive). It is used as a backup in case a disaster happen (like a drive failure). With the drive image software rescue drive and the image itself you can restore the drive as it was on the moment the image was created.
This are the most used drive image software:
- Macrium Reflect Free Trials
- AOMEI Backupper

mridzon said:

And what exactly is a system image?

A disk image is a fancy name for a copy of everything on the disk.
A system image is a fancy name for a copy of everything on the OS disk.
You do not have the access & ability to control the OS necessary for making such a copy.
System imaging utilities do. They are also very intelligent in making the copies, they omit things that are not useful later on such as the hibernation file & paging file.

mridzon said:

What would I potentially use it for?

You would use it to restore the relevant disk / partition back to its state at the time the image was made.
So, for example, if you experimented with some software or settings and it all went wrong, you'd restore the last system image to get back to the state your software was in before your experiments.
If your disk failed, you'd restore the last system image onto a replacement disk to get back to the state your software was in before the failure.

mridzon said:

Can you share tips on how to create a system image?

my ditty - File backup vs imaging, imaging utilities, backing up drivers [post #3] - TenForums
- I use a free version of Acronis TI.
- Macrium Reflect is popular amongst forum members.
- Aomei Backupper - This one has a reputation for being easy to use and it has a free version.
- MS still retain their imaging utility in Windows but they told us to stop using it six years ago. Some people report still using it without any problems but I always found it awkward even before its retirement [its "deprecation"].

Whichever utility you choose, always make & test its boot disk [by booting from it].

{Where Luiz mentioned 'rescue disk' above, do note that that means the same as 'boot disk'.}

If you could not boot into Windows because of some problem, you would boot with that boot disk and you would then be able to run that utility directly from its boot disk to restore an image.
Even utilities that can set up a booting arrangement for you so that you are shown a menu in which you can choose to continue into Windows or into the utility are useless without a boot disk in the case of disk failure.


All the best,
Denis