Doing the father thing and looking at my daughters laptop which acts like a brick since it was auto updated to Windows10.
Though this might help others in the same situation as I've come across this twice now, the first time I came across it I
ended up booting a Windows7 disk and zeroing the HD boot sectors before I could reinstall Win7 to replace Win10. The
data wasn't important and the person concerned wanted Windows7 back so they could use their scanner and printer
again.
Searching both the Microsoft and HP websites on locked harddisk messages when attempting to boot Windows 10 gets me no end of rubbish that is just plain wrong.
I tried this authoritative fix from the HP forums. Similar answers are to be found on other forums including MS's website.
Insert your Windows10 DVD into your DVD drive.
Reboot and select "press any key on the keyboard to boot the computer with the bootable media.
On the first window, select your preferred language, time and currency format, and keyboard layout and click Next.
On the next window, click Repair your computer from the lower-left corner.
This can take up to 3 hours before you are presented with your Options menu.
From the Choose an option window, click Troubleshoot.
Click Advanced options from the Troubleshoot window.
When the Advanced options window opens, click Command Prompt.
This can take another hour before you have your Command Prompt window.
At the command prompt window, type
"Bootrec /fixMBR" <== give this about 10 minutes
then
"bootrec /fixBoot" <== give this about 15 minutes
then
"bootrec /rebuildBCD" <== Give this about 2-3 hours..
Then allow Windows to enter AutoRepair on reboot and go to bed.
The next morning you see the message that the Autorepair has fixed your problems but it also states..
"0 Partitions found"
Reboot and get the same "Disk is Locked" message.
Seems to be a problem with Microsoft's weird container ideas they use for system images.
Give up and boot a linux DVD, see that the Windows partitions are actually there and readable.
Run a Linux based antivirus program and remove the boot infection from "frostwire-setup.exe".
Reboot and it now all works.
Booting from Windows10, running recommended fixes, about 16 hours.
Booting from Linux, antivirus scan and repair, about 30 minutes.
Checking the Linux forums it turns out that simply booting from a Linux CD or DVD and reading the mounted Windows drives fixes the problem. So I could have fixed the issue in about 5 minutes but left the infected file behind.
I've had a few run in's with Windows 10 this year, none of them have been simple fixes, all re enforce my opinion that Windows 10 is a glorified buggy datalogger.
(edited to fix spelling)