Unable to do Factory Reset

My daughter has H.P.Pavilion laptop with Windows 10 O/S. I didn't ask her what version she is using but I think she does necessary updates. She wants to clean off personal data etc. before giving the laptop to a sister. When she goes into "Recovery" and starts the reset process it seems it goes so far and then gets a message saying it is unable to do it. When she tries a slightly different way she gets messages to the effect that the computer needs repair and/or there is not enough RAM to reset.
Perhaps someone could let me know what the problem she might be up against and if there is a simple work around.
Thanks.

As a means of saving all the installed applications as well as all the current Windows updates, one idea would be for you or your daughter to log on as an administrator (she probably is, already), and create a new account in her sister's name. It should 'offer' whether all the apps should be available and maybe (I'm not sure) making the data available as well.

Once the sister account has been successfully created, then delete your daughters' account on the laptop. (Note: Do not delete the last administrator account on the laptop! One idea would be to activate the builtin Administrator account with a unique password) Done. Everything in her documents, emails, preferences, desktop, etc, will be gone.

I'm reasonably sure the new account will come up with a 'Welcome' screen and offer to walk the new user through various options and default settings. You or your daughter may want to set everything up for the sister, including setting up Adobe Acrobat and other settings such as default browser (I'm a Firefox user), and things like that. Depending on choices during installation of those apps, they may already be available to 'all users'.

Thank you all for your suggestions. I now learn that my daughter gets an Error Code 0xc0000017. I googled this and found a suggested fix involving Command Line entry "bcdedit /deletevalue {badmemory} badmemorylist" etc. I am hoping this will help her as doing clean installs or other involved work-arounds may be more than she would want to take on. We live 200 miles apart and I would not fancy trying to solve the problem using "Team Viewer". I may be back.

My thanks to all who responded to my enquiry. I managed to put media creation onto a USB Pen Drive and posted it to my daughter. She managed to do a clean install of Windows 10, as suggested, on her HP Pavilion laptop using the pen drive. She has now provided her sister with a As Good As New 930 GB laptop.