Last night I watched President Obama's Lincoln Day speech on Youtube. The stream kept stopping to buffer, very annoying. This morning, after I started my computer, I tried again. This time there was no problem at all, it ran straight through. Then I tried watching a video of the Colbert report, and another one. There was one interruption for buffering. So I tried a video from The Onion. The repeated-buffering problem returned. Is something filling up on my machine, that I could enlarge or perhaps fix by emptying it from time to time?