Hello Chris, here's a basic tutorial on how to configure QAM channels to receive guide data in WMC using Cable (no cable box).
E.g. Channel: FOXHD.....No data available
Select Tasks: settings
Select Edit Channels
Scroll down and select e.g. FOXHD
Select Edit Listings
Select "W" on the keyboard or remote
Find and select WFLDDT
After selection, FOXHD has been replaced with WFLDDT
Return to the Guide to see the new data.
Before saving, you can configure other channels.
Any channel without a check in it's box is encrypted or either has no signal. The initial setup scan has enabled all unencrypted channels within Windows Media Center, so there's no need to enable any other channels.