How Can I Free Up Space on My C Drive?

You could start with a system cleanup tool that comes with Windows. It’s a simple way to get rid of unnecessary files. Also, consider uninstalling any applications you don't use anymore to free up some space. If the laptop has a lot of duplicate files or temp files, those can be cleaned out too.

Honestly, it might have been better if she had factory reset it before giving it to you! But you can still free up some space and make it work for you.

Don't forget to delete temporary files and clear your browser cache. Moving large files like photos and videos to an external USB can also help make a big difference. If it’s an HDD, you might want to defrag it after you’ve done all that cleaning.

If you're up for it, using something like DBAN to wipe the drive completely and then reinstalling Windows can really clear everything out. Just make sure you have your Windows key handy before you start. That way, it’s like a brand new machine!

If you're okay with doing a bit more, asking your sister about any important files she might need is a good idea. You can create a new profile for yourself on the laptop and delete her old one. A fresh reinstall of Windows would really clean it up, but that's more work.