Would you need a power source? If you aim your ship correctly, then put everything alive into cryo, the ship could go completely dark, vent all heat and become a frozen rock. Then after [very long time] the ship enters the vicinity of a different star and can be reactivated and unfrozen using solar energy. You dont need energy to maintain cryo if the whole ship is at 1° kelvin.
(Of course that relies on cryo sleep being possible)
Deleting a file does not overwrite the data. It just marks that area of the drive as “free”. Using forensic tools (or simply dd) you can read data from “empty” parts of the drive. To be save you have to overwrite each file. You can try tools like shred to scramble the data of a file before deleting it, but as they say themselfes, unfortunately your filesystem might not actually let you do that (scroll to the CAUTION section).
You can use dd to write bytes to arbitrary places of the drive, but again, the filesystem might lie to you where a file is actually located. The ONLY way to be entirely sure is to wipe the whole drive. And if your IT does not do that before handing a system to a new employee, then they are not doing their job correctly.
Not legal advice: just tell them you installed a few viruses (while the system was not connected to the company network of course) and they should nuke the system before handing it to anybody else.
(You can also wipe the drive yourself by booting from a stick and overwriting the entire drive)
A big part is groups selling Yoda plushies to star wars fans, telling those fans to kill people buying bb8 plushies so they don’t loose out on sales. Many (most?) of those deaths are about money and power
Only if they can be turned off (same as the cryo sleep). The whole ship either has to have enough energy to last potentially 100000 years (no theoretical power source exists like that) or enter a state of 0 energy consumption. Solar/radiation collectors dont work if you are to far from a star. Synthetic life still needs energy