Computer keeps restarting?! O.o

[Sakura5]

Hello, my computer keeps restarting and I don't know how to fix it, this is going to be long story but I'll shorten it the best I can:
This computer had windows vista on it and i was able to create an account and after 3 days or so it said something about it not being a genuine copy of windows 😵 now whenever I turn it on it just reboots itself over and over again and never gets to the login screen. So I can't access my account or anything. Can anyone please help me?!?!

 

[penguintech]

you need to install a genuine copy of windows. one that can be activated online. otherwise, you wont be able to log into windows. Microsoft gives 30 days for an unactivated OS to work, after 30 days it MUST be activated. if you do any type of hardware changes, you may receive the message that your system needs to be activated within 3 days, if not activated in those 3 days, again, you will not be able to log in until the OS is activated.