A computer is experiencing random reboots and phantom problem that disappear after rebootwhat should you do?

Simply put? Get a new computer.

If this is not an option, take the computer to a computer specialist and have them diagnose the problem.

If this is also not an option, you may try re-installing your operating system. If the problems persist, your computer is likely experiencing hardware problems, which can not be fixed easily. The faulty parts will have to be replaced; however, purchasing a new computer would likely be a better track to take, as they are extremely cheap nowadays.