Hi, so as I said in the title, my computer with windows 7 gets stuck at "loading operating system..." and eventually after a few minutes says "Boot from CD/DVD:" followed by "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER". When I restart the computer with the Windows disk in it goes to the same black screen and eventually tells me boot from a CD/DVD and "press any key to boot from a CD drive". If I don't press anything it continues to "windows boot manager" and gives me three options between Windows 7, Windows Vista home premium (recovered) and windows 7 home premium (recovered). From this point on wards I can boot up normally (selecting windows 7) and the computer runs fine. If "press any button" then it loads the Windows disk and ask me whether I want to resolve problems or install a new copy etc... I have tried many on the options with no success.
This has been going on for at least a year now.
I should note this happened at the same time (If i remember correctly) my brother decided to install a third hard drive into the computer, as far as I can remember the only problem afterwards was the inconvenience of needing to insert the Windows disk upon reboot. This was never really to much of a concern for us until we tried to install windows 10, we thought it would magically fix the problem (hopeful I know) but instead the installation crashes after 12 or hours of installing. Also one last thing, there's hundreds of updates that we can't install (it gets halfway and then has to revert all the changes it's made..)
Thanks in advance for any help, it would be greatly appreciated.