webcams as security camers

[Leftie]

I have a PC sitting under my desk which we bought a replacement for. It is decent spec but no longer of any use as such.

It has a wi-fi connection, has internet access and is loaded with windows and office.

I have a web cam or two and was wondering how easy it would be to set it up to record enty and exit to our driveway viewed through the study window?

Would it need wpecial software, how much recording could I nmake on 60Gb of spare hard drive and is it possible to set it up to record only at night for example?