|I couldn't find the exact beep code for that model. It may be in the manual.|
But it's either ram or video. If you have a video card card instead of on-board video, try another card. Make sure the card you're using is firmly inserted in the slot.
Did you have the system unplugged when you were inside the case or was it just off? The power supply still provides a small charge to the motherboard when off and that can be enough to ruin something when you're messing with the PC 'innards.
Now that's what I call a sticky situation