Windows XP MCE error help please...

Hello,

I'm currently running Windows XP Media Center Edition on a Sony Vaio Desktop.

I recently installed an ATI Sapphire Radeon HD 3850 (AGP) as well as another 512mb of RAM (bringing the total to 2gb). I'm not entirely sure if that has anything to do with my issue, but the issue is now when ever I try to watch TV I get the error message "Video Error - Files needed to display video are missing or corrupt. Please restart Media Center and/or the computer." I've tried doing both, as well as looking for a codec to install and also trying to see if I could repair or reinstall the Media Center. I haven't really been able to find anything. Any help would be greatly appreciated. Thank you.

Edit: I tried looking in the device manager for the TV tuner, and it doesn't look like it's showing up, but I'm not entirely sure...because I can't remember what it used to show up as. Plus, I don't even know what kind of TV tuner it is since it came with the comptuer.

 

Update: I used system restore to go back to the point before I installed the drivers (and the rest of the stuff) from the disk that came with the video card. I think the ATI AVIVO codec was screwing up my Media Center. I reinstalled the video card driver alone and now it seems to be working normally.