I'm trying to upgrade to windows 10 using the free upgrade option. Currently my HP ProBook 6440b is running windows 7. Whenever I try to start the download, I get the loading screen infinitely- I've restarted it a few times and it keeps on loading for hours. Everything's up to date and I checked my disk for errors. Any help would be greatly appreciated! I'm trying to get my laptop up and running Windows 10 before going to college (and before the free upgrade expires).