windows 10 installation troubles

[UltraVires]

hey guys a non tech dude here asking for advice, i recently just built my first pc out of used components, i have an old hard drive with windows 7 installed. powering it on for the 1st time, cant access w7 getting startup repair errors. got a usb drive w10, installed it, no key ofc, now i cant get to w10, i can access the cmd prompt, tried the videos on youtube about bootrec/fixboot but im getting acces is denied error, tried the rename volume fix did not work for me. has anyone encountered this and can you gimme some direction. i dont have another pc, i do have a laptop to work with, i have ubuntu on another usb and windows 8 already downloaded. 

[Call_Me_Daddy]

Hi !

One of the reasons why you have to install Windows on a new computer is because windows has to adapt itself to your hardware (Motherboard, CPU...).

You won't be able to run windows from a HD on which windows was already installed on another computer. I mean you might if the other computer was using compatible components.

I hope this helps !

[Bruno_A]

Let me see if I got this straight:

• You built a computer with used components;
• The Hard Drive had Windows 7 installed but wouldn't boot;
• You installed Windows 10 from the USB drive;

Is this right? 

You could try and reinstall Windows 10, but this time, make sure the hard drive is clean. You can do this by going through the Windows 10 setup (when booted from the USB drive) and clicking Shift+F10 to open the command prompt. Once the command prompt is opened, type in the following commands:

• diskpart
• list disk (this will list all the drives installed in your system, including removable ones)
• select disk X (Where X is the number of the disk you intend to install Windows 10, most probably will be 0, if you only have one hard drive)
• clean

Once you done this, close the command prompt and if you've done the steps above while on the disk selection (when you choose which disk you want to install Windows 10 on), make sure you refresh the disk list (only one disk should appear). Select the disk and proceed with the install. Let me know how it went.

[UltraVires]

holy shite, im actually a dumb f***. i wondered i kept getting prompted back to installation screen in windows, IT WAS because i forgot to set the boot drive back to the hard drive after installation, so i got 4 windows10 installed and a w7 on my drive because i kept reinstalling using the usb as the boot drive. i am so sorry to waste your time, thank you for your suggestions, i bet that diskpart clean would have solved the issue .