Macbook is super slow but it's not a problem with the internet connection

Hey,

So my problem is with my 2 year old Macbook. I have experienced problems in the past with indexing that say they will go on for the next 674 years, but I got someone to fix that for me, by resetting my computer. About a month after this my internet (I am still using Safari) just stopped running like it normally did and now it takes an average of 20 - 30 minutes to open a simple web page. After getting Safari closed again the entire computer runs crazy slow until I reboot. Recently the same problem has spread to my iTunes. I will be using it normally and then it just slows down and that frustrating spinning color wheel pops up. With my iTunes it only happens some of the time though. I have run several different virus scans with several different programs and they all come back completely clean. Does anyone have any idea what the problem might be and how I could fix it?