Vague and nebulus question...
If you could be more specific, like what media is the 'video' on and what are some specifics of your computer (system?), your answers may be more helpful. But I'll give it a stab anyways.
By 'system' I'm going to assume you mean "computer"
By video I'm going to assume you mean "some version of television, be it VCR tape, Tivo, dvd, or possibly video camera of some sort"
A recording on optical media can be ripped (imported to your computer's hard drive) by a DVD reader/recorder and the appropriate software.
Or if your 'video' is on some sort of memory... flash or hard disk, the appropriate hook up (USB 2 or Firewire or maybe USB 1.1) and the right wire (and/or memory reader) can be used import the aforementioned 'video' to your 'system'.
In any case these are the methods I use as I do not have 'video inputs' on my 'system' either.