Do an internet search to verify.
Best I can recall if turn on the computer for say 15 second and then turn off and do this 3 or 4 times (quickly) in a row the computer will go into trouble shooting mode and you should be able to gain access to it.
You might be able to download a free new windows software but you may need the license number. But you should be able to download Linux operating system for free.
https://www.linux.org/pages/download/
You might try any power supply you have before you buy a new one.
I did get my computer working when a virus took over doing the above but I did know my password and license although I do not remember how important that info is if you want to wipe the computer clean.