Windows 10 stuck, in windows defender check at boot (infinite loop)

Good evening!

I recently started using my older laptop which has windows 10. I restarted my laptop after normal use and it started doing automatic repair. Windows defender check up starts running every single time. Sometimes it finished and sometimes it doesn't. Every time after the completed or failed check up, the laptop restarts and does it again (~15 times now).

- Windows 8.1 installation disk has been inside the machine for last three hours (~5 restarts)
- USB-stick with windows 10 installation media made with rufus has been plugged for almost the same duration.

DVD-drive starts up during restart, but the installation doesn't start
Laptop doesn't react USB boot device. (Device works since I've tested it on this PC and used same device on this PC).

I've installed windows to various PC's several times including the laptop in this case, so I have knowledge of the basic installation procedures. The laptop doesn't react to boot devices and BIOS can't be accessed via hotkeys during boot.

I've been browsing forums and web pages for last three hours and haven't found any working solution.

Any advice or stuff I should try?

Thanks for the reply!

cottonball said:

Windows 8.1 installation disk has been inside the machine for last three hours (~5 restarts)
Aren't you trying to work with Windows 10? Why would you have an W8.1 installation CD in the drive?

I wanted to try installing windows 8.1 as a last resort, because installing windows 10 didn't work.

cottonball said:

USB-stick with windows 10 installation media made with rufus has been plugged for almost the same duration.
(Rufus is not considered a very reliable way to prepare a USB flash drive that will boot.)

I forgot to mention that I also tried making a boot media with Microsoft's own tool (same as in your link). No success.

cottonball said:

You also need to select the drive from which to boot in the Boot Order section of the BIOS.

As I mentioned in my original post, BIOS can't be accessed. I have tried accessing it for hours and dozens of start ups.

Since the laptop doesn't have so much value to me, I will try removing the hard drive and force it to start up to BIOS. Removing the possibility of Windows running the offline defender during boot, seems to be the only solution at the moment...

I'll be back with results.

I removed the HDD from the laptop, plugged it to my main PC, erased it with CCleaner and put it back to the laptop. Windows 10 installation process started normally from USB media, on second try.

- Ville