Interlacing problem

[gksdfjghe98]

I'm not entirely sure if this is a GFX card problem or a Monitor problem so if I've posted it in the wrong forum I apologise.

I'm having problems with video playback on my system because of a horrible 'scan-line' effect from what looks like interlacing. It's not a massive problem as movies are watchable from a distance, although this is my monitor so 99% of the time I'm up close and personal. I don't get this effect while playing games. I'm not exactly sure what is causing it and I can't seem to find anything on Google that addresses a similar problem so I could simply have something configured incorrectly.

Relevant specs:

• 2 x XFX Radeon HD 4890 (in Crossfire)
• Hyundai W240D 24" Monitor

The monitor is connected via HDMI using the adapter that came with my graphics card. I have tried disabling crossfire and changing resolutions and I've had a quick gander through the Catalyst Control Panel but I haven't seen anything that I understand would fix it.

Any input is appreciated. Attached is a screenshot of my Windows Media Player in action. If you need any more info, just ask

 

[gksdfjghe98]

I'll get some codec packs and re-evaluate the situation. Hadn't thought of that. I'll update when I've done so.. There's a problem with my exchange at the moment so my internet connection is half-arsed and comes and goes as it pleases. Cheers.

--Edit--

Seems to be working a lot better now. The help is much appreciated!