Have videos played normally in the past? Do you mean the videos lag or just take a long time to load? Have you checked the amount of free space you have available on your hard drive? If not, check and see how much space you have available. If the disk is nearly full try clearing temporary Internet files and deleting files you no longer need/want. If you aren't sure what the file is then do an Internet search to make sure it is not a system critical file before you delete it.