To add on to MrPogi, are you getting any VHF channels, including VHF-Hi (7-13) or VHF-Lo (2-6)? In your case, these would be 33-1 (RF 5), 9-1, 6-1, 11-1, 13-1, and the more-distant 12-1 and 8-1.
If you're not receiving these VHF-band channels, it's likely your antenna isn't picking up VHF. If you are, then something is interfering with your signal, and there's any number of things that could be causing it.
We had this same problem. We had an analog TV with a digital box converter and we could always get ABC. When we got an HDTV, we could never pick up ABC and there was no way to search again for other channels. In our area (Spokane, WA) ABC was channel 4-1. I went to Complete List of TV Stations - Station Index and found our TV market (on the right they have Top 100 markets and small markets). I found the one for Spokane and they list all the local networks. I clicked on the ABC network and it said it was channel "4", but below that it said "DTV/HDTV Channel 13". So, on a whim, I entered channel 13-1 onto our TV and the ABC channel started working! But what was strange was that it now calls the channel 4-1 and is between channels 2 and 6 on our TV. So maybe with ABC there is something that HDTV just have to recognize to start working. Hopefully it works for you!