Log into the old domain profile, run the transfer files and settings wizard to copy the profile to another location on the drive (like C:\profiletrans).
Then log into the new domain profile, and once again run the transfer files and settings wizard to transfer the profile from its new...
You would probably have to buy a new vista pc that includes one of ati's new hd tuners. Unfortunately, you cant buy them separately.
Due to all of the DRM restrictions vista has on cable hd, you're honestly better off getting a cable company hd-dvr.
this is exactly why i went with the hd dvr offered by my cable company. With all of the DRM restrictions and installation hassles, there is NO real benefit to getting a cablecard enabled pc.
not going to happen anytime soon.
i ended up deciding not to get a cc enabled pc from velocity micro for one reason: you cannot play back hd recordings on any pc other than the one it was recorded on. because of that, i decided to get the hd cable box from my cable company.