Computer Running Slow: System Making Unwanted Sounds?

Unusually slow system; unsure where to go from here.machine runs very slowly for the processor and for the amount of processes running.There is some degree of visual skipping/slowness,it is particularly apparent with audio and visual media. Even the startup sound is very drawn out and is characterized by a long, skipping echo. Music skips randomly and even alert noises, (such as the one heard when ending a process) has the same skipping/echo. This happens even when there are few apparent processes running and very little CPU usage (such as 5%), as well as when the system is overloaded (which happens remarkably quickly for the 20-30 processes running).