BleepingComputer.com: No Sound, Video Not Working Properly

I have a Gateway laptop that runs Windows Vista Home Basic. I purchased the laptop early in the summer and until recently I've had no issues. I can get NO sound from my computer at all. The volume is up and the mute is off. It doesn't even play the windows start up sound anymore. About two weeks ago, I turned it on and everything looked different. As if the screen resolution had been changed. I checked that and it was the same as I've always had it. My icons and fonts and look bigger and sort-of blurry and my screen looks ever so slightly compacted and stretched out. If i try to play video clips, it plays "jerky" or about 2 seconds at a time. The videos play like I have dial-up (even though I have a cable connection). They DL just as quickly, but they play slow. Can anyone offer any suggestions??