First of all make sure you're not putting the disc in backwards. The label on the disc should face away from the buttons and the SD card slot.
If something is unknown it is not known by someone or something.
It is unknown if computers will replace books in the future.
Which problem are you refering to, because otherwise we cannot answer.
A variable is something that represents, or stands in for something unknown, for example a number. You could be given the math problem 6 + x = 9, in which you would have to figure out what the variable is, which, in this situation, is x.
The antonym of unknown is known. When you know something then you won't not know that thing that you know. Unknown means to not know something.
Because its cut
There might not be a problem which makes you think there is one
An unknown problem is just that. It is a problem that is unforeseen or that a person is not aware of. When there new programs being release there are sometimes problems that are unknown.
Unknown
something that is unknown
as an adjective (problematic) it is problematicus. As a noun it is unknown to me
A variable is representative of an unknown quantity in a problem.