Lines in picture, HDTV PCI Card

[dnbrvr]

I have recently built a HTPC with an ADSTech Instant HDTV PCI card. I have an XFX Geforce 8500GT PCIe hooked via HDMI to an Epson Powerlite Home Cinema 1080P w/ 106" screen.

Both projector and video card are set at 1080P/60Hz. Projector actually shows 1125P as resolution.

I can view a bunch of HD & DTV ATSC channels very nicely from an over-the-air amplified antenna (Vermont, USA). But I can see lines of resolution in motion/action scenes.

I have tried with the tuner card set for deinterlacing both on and off.

Does anyone have any ideas of settings I can try to tweak to get rid of the pesky lines? For instance, I watch football live and it looks great until everyone starts running.

Thanks!

[dnbrvr]

Thesea are the rest of the components in my system:
Windows Vista Home Premium 64
Intel Dual Core Duo Conroe 6550 233/1333
Gibabyte GA P35 DS3L
4 x 1GB Gskill PC6400 memory
2 x WD SE16 500GB SATA II HDD
1 x WD SE16 320 GB SATA II HDD (OS)