Pc not booting after deleting Norton

So my brother has had Norton 360 (or Norton lifelock, not sure, just some kind of Norton software) for a long time and he doesn’t really know why, but he is just now deciding to get rid of it. He installed the dedicated uninstall tool from Norton and now his computer won’t start. I turned it off and on and noticed that, at first, the VGA motherboard light was on, followed by a message on the monitor saying there was some kind of disk repair needed, and that it would take over an hour. After about 10 seconds, it said it had a problem booting and would restart. The computer restarted and now the CPU light is on the motherboard and the monitors have no signal. Is he screwed? And why would deleting a software cause this? I know Norton is shit, but..