put in new video card

Put in new video card, monitor doesn’t light up, monitor works on another computer. computer with new video card is running, fan, etc. beeps 2, then 2, then 2. can you help me? before I put in new video card, was playing a game. then I changed irqs, port. may have gotten ports crossed. Was trying to get my modem to work, it wouldn’t work, put in new serial card for mouse. mouse card and modem card would not work at same time.