New to RokuHD1k product

I recently got one and I am fairly thrilled with it.  Looks like poeople are
doing cool stuff with them.  I wish I understood a little better some of the
details that people talk about here.  My big question regarding playing back
video stored on a PC is 'Where can I acquire a HD signal to store for later
playback?'  I bought a MYHD video capture card with the understanding that
it would not be able to record HI Def directly from the cable (Dam Digital
rights managment)  The catalog did speak of a VGA input so I nievely thought
I might be able to record from this HD analog input port.  Turns out they
meant it could be used in a pass thru mode where it could share the monitor
with the normal PC video card output. No recording of signals from the VGA
port. (foiled again)  In the mean time I have a Hauppauge USB2 video capture
device that works pretty good on ordinary cable signals, at least way better
than VHS.
JB