You would have to be recording beforehand for this to work. There is no way, short of some hereto unknown law of physics allowing for practical temporal warping on a very small and controlled scale, to do what you want with any software or TV card. The ONLY option is to just record everything, and then throw out what you don't want.
I was wondering if i could record a non-live tv signal through media center. when i pause or rewind live tv and press the record button it starts recording the live signal (which is a minute or so ahead of what i'm watching) and not the delayed images that i was watching. i believe media center records the tv to a temp rec folder and that is how it allows the live tv to be paused or rewound. my goal is when i see something interesting on tv while i'm not recording, rewind the tv and then record it. is this possible with media center or with any other program that utilizes my tv tuner.