FPS Problems

I been using this computer for the past few years (Dell Latitude D520) and its always ran fine. I have upgraded the memory to 2GB and also the Hard drive to a 250gb. I mainly use the laptop for playing World of Warcraft now that im out of school. It seemed to have just happened over night and my frames per second have went from about 30-40 in-game to 4. I have changed and tinkered with every possible option to help maximize my FPS but nothing has seemed to work. Does anyone have any ideas to why my computer has suddenly went into a fps coma? Im hoping to track down the problem before i decide to format everything and start over.