Slow and Skipping
My Macbook pro is about 3 or 4 years old. It has never given me trouble. All of the sudden the last 2 weeks it has been getting slow. Its progressivley getting worse I can barely type without it pausing and giving me the wheel. I can't multitask and its now not playing video or music without skipping, pausing randomly and then there is no sound at all. I have tried several different virus scanning and cleaning techniques and none seem to help because they all say nothing is wrong. There is no unusual sound or anything I can find thats wrong. Battery doesn't seem to be decreasing at an unusual rate.
Does anybody know what is going on and what I do about it? Need more information?
Please and thank you!
MacBook Pro (13-inch Mid 2012), OS X Yosemite (10.10.2)