ok...i do have a hauppage tuner card that is installed but i have not used. so where does that put me?
For starters you'll need the camera and receiver plus a motion detector, although X-10 sells a camera/motion detector combo unit.
An X-10 VCR Commander can receive the RF signal from the motion detector and emit an IR signal to start a recorder.
An X-10 TM751 or RR501 Transceiver can receive the RF signal from the motion detector and send a powerline signal to turn on the camera power supply, but if you're using only one camera I suppose you can just leave it running 24/7.
(Even though the camera video signal is wireless, you still need to run power to it - it may or may not make more sense to use one of their wired cameras, depending on the location of your PC and the type of construction the RF video signal would otherwise have to pass through.)
Presuming you want to use your TV tuner card and the software supplied with it:
My Hauppage tuner card came with an IR remote and a plug-in IR detector cell. (I've never used it.) If yours does, hopefully it will be compatible with the VCR Commander's IR learning capability. (Check the VCR Commander Owner Manual on the X-10 website to see what it's all about.)
As a backup I'd look to acquire the VA11A Video->USB adapter. It's included with some of X-10's camera bundles so may not cost you any more.
Disclaimer: My actual experience with these cameras is limited. I once recorded a guy pilfering in my house, but knew when and where the suspected perp would be. I ran the cable from a hidden X-10 wired camera to my tuner card and sat upstairs watching the activity on my PC monitor, manually turning on the recording function when he arrived.