Some info on what type of system you have would help. Also does the sound come from the external speakers or the computer's internal speaker. If it's the internal speaker then this may be an alarm from the BIOS telling you that there's some problem on the motherboard like a CPU fan not spinning etc.
You may have a resource conflict with your sound card and another device in the system that's causing the sound and video to lock up. If you can't get past this even in safe mode try removing the sound card and see if it comes up. If the sound is intergrated onto the mother board it can be disabled in the system BIOS. If the computer boots without the sound then at least you've found the problem. The next thing would be to figure out what device is causing the conflict. If your sound card is in a PCI slot and you have one available try moving it to another slot. Some motherboards allow you to set the PCI IRQ's but all are a bit different. So that's why I say to try another slot.