Slow streaming on my laptop.?

I have a Sony Vaio laptop that is just over a year old. About 4 months ago I dropped it on a tiled floor and thought I had broken it for good but after an hour or so it came back to life! It then continued to work for another couple of months (with lots of whirring noises) but gave up about a month ago. I have had it repaired as I needed a new hard drive. It is fine now apart from it won't stream video's instantly anymore. My internet connection is the same and even after I had dropped it (before the new hard drive was installed) the streaming was fine. Does anyone know why this is? Is there anything I can do to speed it up again? Many thanks x