Laptop hangs at Starting Windows, can't boot from external device.

So I recently went to change my laptop from windows 8 down to 7. To do this I just had my installation disc, ran setup, and let it do its thing, resetting itself applying updates etc.
When I came back a few hours later it was stuck on Starting Windows with the logo not even pulsing. Restarting doesn't help, safe mode gets stuck at disk.sys and no matter what key I press I can't enter the BIOS.
I'm unable to launch my installation disc or a USB booter.

I can't find a solution I can even try anywhere! Can anyone help?
Thanks.

Yeah I did when I thought the only way I could install windows was from booting into the disc.

I used the disc on another PC of mine just a few days before and it was fine then. And no I never disabled UEFI boot :/

Does anyone else have any suggestions?

anyone? D:

AddRAM said:

You have to disable efi and enable Legacy boot, windows should then install no problem.

But I have no way of entering the BIOS in order to enable legacy boot. No button I press does anything other than take me to the start windows in safe mode menu :/