You might notice the lack of answers to this question. That is because you can buy a used TiVo for almost nothing on ebay, put in a big hard drive (>250GB), subscribe to the TiVo service for three years and be done for less than $500. Building a PC that can handle multiple TV signals will run you $1000 or more. From most TiVo users perspective, the aggrivation and extra cost is just not worth it.
However, if you are interested in finding out how to do it your self, google MythTV or SageTV. Or look here. That will get you started.
Good luck.
However, if you are interested in finding out how to do it your self, google MythTV or SageTV. Or look here. That will get you started.
Good luck.