microsoft 10 install has been

[WPCentral Question]

I clicked "lets get started and it has the little bubble circle in motion and the words in the box is "working on it" for 3 hour now. I am going from Windows 7 professional to Windows 10 on a DELL Latitude D830. Microsoft did pre-verify that my system is compatible, I am thinking I do not have the hard drive space. I want to stop the process. Can I do so?