Purchased used computer - changing settings help

Purchased an HP laptop from a friend. It is only a few months old. He has microsoft office on the computer, so i do not want to wipe the computer clean.

Hopefully this is an easy question. How do I remove his name and password from the computer, particularly on the log in/startup screen? I have his password to sign on, but i want to personalize it to my information.

Thanks in advance
Drew

edit: it is running windows 8.1

I know you can do a factory reset and I don't think you can take over his Microsoft office also it does come with office installed

hTconeM9user said:

I know you can do a factory reset and I don't think you can take over his Microsoft office also it does come with office installed

Click to expand...

You can if they hand you the license. I did that with one I gave to our church. I had downloaded Office 2k10 through ultimatesteal.com. Just wrote a quick note that stated the system was gifted to the chirch, along with the software that was installed.

See here for how to rename an account: How can I change user name of taskmanager processes? - Page 2 - Windows 7 Help Forums

I vote to pull the Licenses of everything, Nuke & Destroy the OS and installed software, so that there is no possibility of Malware. Then reinstall the OS & Office. There should be a "Trial" for Office 2013 installed. If you do decide to Nuke and destroy the existing install, Follow these instructions to turn the Trail version of Office 2013 to Full. How to Convert Microsoft Office 2013 Trial Version into Full Version without Reinstalling? - AskVG

Thank you for all the responses. Much appreciated.