Safe? What exactly do you mean by safe? No matter what prophylactic method is used to protect it (even taking it offline and turning it off) if it has information on it someone wants they can get it, even if they have to break into a locked building and steal the computer that information isn't absolutely safe, so conceivably saying no computer is safe, as Trump recently said, is absolutely true.
It is also absolutely true some computers are safer than others, that's a given even though nut cases like Hillary Clinton apparently had no idea that is the case, now she does. Shame her ignorance of that lost her the election, (or was it a blessing?).
Anyway, I have often wondered why computers aren't configured to shut down instantly upon any unauthorized intrusion, by a hacker for instance. I had a computer that shut itself down sporadically for no apparent reason! Wouldn't you think that someone would come up with a program that would shut down the hacker's computer if he broke into a firewall, isn't a breach a two way street?
What really boggles the mind is why, if people have something they want hidden, why would they even use a computer to transmit it over the internet, there are other secret ways to communicate that can't be hacked like the DNC emails were hacked. Or were they? There is evidence those emails weren't hacked but handed over by someone in the DNC who had access to them. For one, Wikileaks founder Julian Assange, whose hacktivist organization released the thousands of emails that shed damaging light on Hillary Clinton and her allies, denied the Russians were the source.
In addition, the Obama administration has developed a reputation for manipulating intelligence for political purposes. In August, a congressional task force confirmed allegations that senior U.S. Central Command leaders manipulated intelligence assessments in 2014 and 2015 to make it appear that Obama was winning the war against ISIS.
Rep. Peter King, R-N.Y., a member of the House intelligence community, has charged CIA Director John Brennan was orchestrating a “hit job” against President-elect Donald Trump by going around the intelligence community and leaking information to the press suggesting Russia was behind the hack of Podesta.
Here is a computer safety tip, either keep no damaging secrets (or at least keep them off computers) - common sense that could promote morality in politics.