Fryed a motherboard I think...

Alright guys I made a big mistake I think here's the background. I've got a slew of parts on order for a build I'm doing. The video cards and the OS came in today. My old system is a pentium 4 pcie 1.0 with like a 800mhz bus. I pluged in one of the new cards a ATI HD 4890. I was able to hook it up with the 900w power supply I already had in the system but both moniters had the same view and the drivers wouldn't install so I shut it down. The system was only on for a few minutes. And when I went to swap cards the 4890 was really hot. It was a tight fit against the sound card. When I put the ati hd4650 back in and started up it wasn't seated properly. I shut down and reinstalled the card and then I got four different pitched tones on startup "high" "low" "high" "low" right before it clicks back off. The motherboard is from a gateway 506gr. I'm wondering if the new card fried the board or maybe the old card an ati hd4650 shorted something out when i started it without having it completely seated.