Computer Monitor Problem

Hello everyone! The problem I'm having is that my computer no longer recognizes monitors. I was using my computer three days ago on Friday when I had a few problems. The computer froze twice while playing World of Warcraft and I had to restart the system, but the music I had playing in the background still continued, even changing songs. The third time, I managed to use WoW for a bit before shutting down my computer successfully. However, when I tried turning my computer back on an hour later, the computer started up, I could hear Windows start up and even Avast updating, but the monitor wasn't showing an image. I also hooked my tower up to a friend's monitor, and that monitor wouldn't display either. I'm worried that my videocard may need to be replaced, and I opened up and aired out my computer. I'm just wondering if there's any way of fixing my video situation without buying a new video card. Any help would be greatly appreciated. Thanks again.