XP? 2K? Surely you want to find the least resource-hungry OS for a task like this? There are a large number of Linux-based PVR tools available and in development, which ought to run like a dream on the EPIA boards.
As one example, check out
VDR. This is for the DVB (digital satellite + terrestrial) cards, e.g. the Hauppauge Nova-T, Nova-S. The developer of the software runs his PVR machine with a K6/2-450, 128MB RAM, UDMA-33 drive!
Also, take a look at
Freevo - nice!
Lots more useful info at
LinuxTV