We're seeing a few interesting Windows 10 upgrade issues as everyone takes advantage of the free update before the end of July. We've got a pretty packed schedule updating businesses before the deadline. Its definitely worth doing, especially from a performance and security point of view.
Just had a Dell Vostro 3550 which was on Windows 7 Pro. Initial stages of the update progressed normally but then we got a completely blank screen (that model uses the Intel HD 3000 graphics adapter). We could see a lot of hard disk activity but no messages - it stayed like this for over 30 minutes.
We didn't want to cancel the install and have to revert, then start again - possibly with complicated restore issues. However we spotted on an external monitor connected via VGA that the mouse pointer was still visible.
We then found that pressing Ctrl-Alt-Del brought up a menu and Task Manager would show processes, but 0% CPU. You could just see a 'Preparing Security Options' message flash up in the background as the menu appeared.
In the end we had to do a reboot from that menu. There was no uninstall fortunately, the laptop rebooted normally but still no display on the laptop monitor. However we did get a desktop on the external monitor. Windows 10 had completed but was suffering repeated file explorer crashes and restarts.
► The fix to get the laptop monitor working was to upgrade the BIOS from A10 to version A12 (use an external monitor).
► The fix to stop Explorer crashing was to uninstall the IDT audio software.
We couldn't actually get to the Control Panel because it crashed every time the mouse moved over. Top tip - in the Cortana search box (or in the Run box - press Win-R) type APPWIZ.CPL to go straight to Programs & Features.