Windows 7 - windows 7 to HDtv through HDMI not working

randomly, as far as i can tell, decided to stop working.

if i have my computer connected to the tv during bootup, it shows up perfectly fine. as soon as the windows boot up graphic disappears, what should show up is the log in screen. this does not happen. my computers monitor goes blank, and my t.v. tells me that there is no longer an input.

the same thing happens and it stops working if i allow my system to boot up before i try to plug it in. once i plug the HD cable in, monitor goes out and the t.v. says no signal.

i'm not sure if this is a graphics card question anyway, but it sounds like it to me. any advice would be greatly appreciated. thanks in advance!!

You may have to uninstall the drivers or any other cards for your current card to work. I ran into this similar problem and it was because I didn't disable my built in graffix card. Go to control panel, system, device manager, and right click on any other graffix cards or GPU chips, right click, and select uninstall or disable. sometimes you have to enable your card in your bios as well right when your comp starts. If these dont apply to you or its your origional card you may have to get some more tips bud. Hope you get it working, take care!

severenc3, you helped out a lot, thank you. this didn't solve my issue directly, but you got me to where i needed to be to fix it. i tried disabling it, and that gave me a weird screen and then i enabled it again. when i did it gave me a striped screen on my t.v. so i thought i would try to roll back the device driver, and that works great. i can see the screen on my t.v. again.

another small question, i have a few small red lines on the black parts of the screen and blue lines on the white parts..... any idea how to get that off there? anyone?