Video skipping

Over the last days any video I play is skipping. YouTube, Netflix, videos played through ProPresenter, etc.

Also the mouse will lag as I move it a cross the screen. Things I click on will not open as fast as normal and then the screen freezes then the app will open or random things happen.

I have

64.67 GB on disk

Memory 4 GB 1067 MHz DDR3

Processor 2.4 GHz Intel Core 2 Duo

Graphics NVIDIA GeForce 320M 256 MB

Software OS X 10.8.2 (12C60)

Model Name: MacBook Pro

Model Identifier: MacBookPro7,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2.4 GHz

Number of Processors: 1

Total Number of Cores: 2

L2 Cache: 3 MB

Memory: 4 GB

Bus Speed: 1.07 GHz

Boot ROM Version: MBP71.0039.B0E

SMC Version (system): 1.62f7