I did this recently and the HP Tech was able to remotely access my PC from the Internet and do the needed repairs. While this PC is still under warranty, you should contact HP Customer Support directly to have them put you in touch with HP Technical Support to see what they can do about troubleshooting and repairing your machine remotely. You paid for free HP Tech Support as part of the warranty coverage, so you might as well make use of it. CTRL ALT DEL usually has no apparent response from the host PC. From several blogs, the cause is apparently that UAC has to be ENABLED, which in my case is not a problem, because I always leave UAC on under Windows 7.
You should not have to enter Ctrl-Alt-Del as that launches the Task Manager, which you do not need to do to login to Win10. NO CONTROL+ALT+DEL: What it can’t seem to do is consistantly get past the Windows Login/Logon screen. When I boot my PC, I get the wallpaper, I press any key and I get the prompt to enter my password. Your description, it sounds like there's something wrong with the Win10 setup.
