How to remove old unused files from windows10 (upgraded from Windows7)

Hi TenForums Team!!!
i have Dell Inpiron 3420 Laptop. Windows7 Home Basic was my built-in OS. Now i have upgraded it to Windows10 Home Edition. Now i have left less space in my C-drive. So i want to delete unused files, folders from C-drive. please guide me. and i also want to backup my windows10 too.

run cleanmgr

Olivir2014 said:

There is a Windows_old folder on your C:, you can delete this - but then you have no option for 30 days to roll back to your Windows 7. Basically, after these 30 days a task is run to delete precisely this folder.

EDIT: You can always make a clean install of your Windows 7, should you want to go back.

what will happen if I delete "window_old" folder now ? Screen shot also attached of C-drive.

Marron said:

Short answer is Disk Cleanup. You should NOT simply delete windows.old.

However, what I like to do is clean install.
Just download microsoft's official upgrade tool: Windows 10
Plug in your USB, run it, and select 'Create USB for other PC', or something similar, wait for usb to be created, boot from usb and do a clean install.

Good info and saving this to keep.. Thanks for all... Cliff M.

acmanten said:

Good info and saving this to keep.. Thanks for all... Cliff M.

It got edited for additional info. Don't miss it. (your quote doesn't have the edit)

Marron said:

Short answer is Disk Cleanup. You should NOT simply delete windows.old.

However, what I like to do is clean install.
Just download microsoft's official upgrade tool: Windows 10
Plug in your USB, run it, and select 'Create USB for other PC', or something similar, wait for usb to be created, boot from usb and do a clean install.

EDIT: Forgot to mention. Do this after you successfully upgraded once, 'cause once a machine is activated on Windows 10 it'll stay activated after the clean install too, but if it wasn't activated before it won't activate with the clean install. And when you're required to enter keys, just skip (you'll be prompted 2 times).
To check if your windows is activated, do 'slmgr /xpr' in cmd.

with clean install i will lost my registerd/activated windows. Actually, i have upgraded my Windows 7 Home Basic to Windows 10 Home Edition. this windows 10 is activated as my windows 7 was. so my question is if i tried a clean install my windows will be activated or not ?? sorry for my weak english.

ifi said:

with clean install i will lost my registerd/activated windows. Actually, i have upgraded my Windows 7 Home Basic to Windows 10 Home Edition. this windows 10 is activated as my windows 7 was. so my question is if i tried a clean install my windows will be activated or not ?? sorry for my weak english.

Yes, if you clean install after your Windows 10 was once activated, it will be activated after the clean install too. Sorry if I wasn't clear the first time. Again. If you do a clean install on a machine that had Windows 10 activated on it, it will activate itself after the installation.

Now if you're wondering 'how', Microsoft takes the IDs of the machine's components and uses them to calculate a hash value. That's why Windows 10 is a 'hardware bound' upgrade. It'll work on that machine, it may not work if you change some parts of it. Now if you're using a laptop, you'll simply stay activated.

Windows 10 is an upgrade 'for the lifetime of the machine'. So if you do a clean install you won't lose your license.

Marron said:

Yes, if you clean install after your Windows 10 was once activated, it will be activated after the clean install too. Sorry if I wasn't clear the first time. Again. If you do a clean install on a machine that had Windows 10 activated on it, it will activate itself after the installation.

Now if you're wondering 'how', Microsoft takes the IDs of the machine's components and uses them to calculate a hash value. That's why Windows 10 is a 'hardware bound' upgrade. It'll work on that machine, it may not work if you change some parts of it. Now if you're using a laptop, you'll simply stay activated.

Windows 10 is an upgrade 'for the lifetime of the machine'. So if you do a clean install you won't lose your license.

Thank you Marron for your good behavior and support. i will mark as solved if it worked for me. and one more thing would you please guide me if i did a clean install with "windows 10 PRO" instead of "windows 10 HOME Edition" would it be activated or not as home edition was ?